diff --git a/lib/fake_matrix_api.dart b/lib/fake_matrix_api.dart
index b1e80ed9..f0f2d16d 100644
--- a/lib/fake_matrix_api.dart
+++ b/lib/fake_matrix_api.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/matrix_api_lite.dart b/lib/matrix_api_lite.dart
index 3a638c49..d6251d92 100644
--- a/lib/matrix_api_lite.dart
+++ b/lib/matrix_api_lite.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -24,17 +23,32 @@
 
 library matrix_api_lite;
 
-export 'src/matrix_api.dart';
-export 'src/values.dart';
 export 'src/generated/model.dart';
-export 'src/utils/logs.dart';
-export 'src/utils/map_copy_extension.dart';
-export 'src/utils/try_get_map_extension.dart';
+export 'src/matrix_api.dart';
 export 'src/model/algorithm_types.dart';
+export 'src/model/auth/authentication_data.dart';
+export 'src/model/auth/authentication_identifier.dart';
+export 'src/model/auth/authentication_password.dart';
+export 'src/model/auth/authentication_phone_identifier.dart';
+export 'src/model/auth/authentication_recaptcha.dart';
+export 'src/model/auth/authentication_third_party_identifier.dart';
+export 'src/model/auth/authentication_three_pid_creds.dart';
+export 'src/model/auth/authentication_token.dart';
+export 'src/model/auth/authentication_types.dart';
+export 'src/model/auth/authentication_user_identifier.dart';
 export 'src/model/basic_event.dart';
 export 'src/model/basic_event_with_sender.dart';
 export 'src/model/basic_room_event.dart';
 export 'src/model/event_types.dart';
+export 'src/model/events/forwarded_room_key_content.dart';
+export 'src/model/events/olm_plaintext_payload.dart';
+export 'src/model/events/room_encrypted_content.dart';
+export 'src/model/events/room_encryption_content.dart';
+export 'src/model/events/room_key_content.dart';
+export 'src/model/events/room_key_request_content.dart';
+export 'src/model/events/secret_storage_default_key_content.dart';
+export 'src/model/events/secret_storage_key_content.dart';
+export 'src/model/events/tombstone_content.dart';
 export 'src/model/events_sync_update.dart';
 export 'src/model/matrix_connection_exception.dart';
 export 'src/model/matrix_event.dart';
@@ -53,22 +67,7 @@ export 'src/model/sync_update.dart';
 export 'src/model/third_party_location.dart';
 export 'src/model/third_party_user.dart';
 export 'src/model/upload_key_signatures_response.dart';
-export 'src/model/auth/authentication_data.dart';
-export 'src/model/auth/authentication_identifier.dart';
-export 'src/model/auth/authentication_password.dart';
-export 'src/model/auth/authentication_phone_identifier.dart';
-export 'src/model/auth/authentication_recaptcha.dart';
-export 'src/model/auth/authentication_third_party_identifier.dart';
-export 'src/model/auth/authentication_three_pid_creds.dart';
-export 'src/model/auth/authentication_token.dart';
-export 'src/model/auth/authentication_types.dart';
-export 'src/model/auth/authentication_user_identifier.dart';
-export 'src/model/events/forwarded_room_key_content.dart';
-export 'src/model/events/olm_plaintext_payload.dart';
-export 'src/model/events/room_encrypted_content.dart';
-export 'src/model/events/room_encryption_content.dart';
-export 'src/model/events/room_key_content.dart';
-export 'src/model/events/room_key_request_content.dart';
-export 'src/model/events/secret_storage_default_key_content.dart';
-export 'src/model/events/secret_storage_key_content.dart';
-export 'src/model/events/tombstone_content.dart';
+export 'src/utils/logs.dart';
+export 'src/utils/map_copy_extension.dart';
+export 'src/utils/try_get_map_extension.dart';
+export 'src/values.dart';
diff --git a/lib/src/matrix_api.dart b/lib/src/matrix_api.dart
index b1484441..88859870 100644
--- a/lib/src/matrix_api.dart
+++ b/lib/src/matrix_api.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 *
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -29,6 +28,7 @@ import 'dart:typed_data';
 import 'package:http/http.dart' as http;
 
 import '../matrix_api_lite.dart';
+import 'generated/api.dart';
 import 'model/auth/authentication_data.dart';
 import 'model/events_sync_update.dart';
 import 'model/matrix_connection_exception.dart';
@@ -41,8 +41,6 @@ import 'model/third_party_location.dart';
 import 'model/third_party_user.dart';
 import 'model/upload_key_signatures_response.dart';
 
-import 'generated/api.dart';
-
 enum RequestType { GET, POST, PUT, DELETE }
 
 String describeEnum(Object enumEntry) {
@@ -55,11 +53,13 @@ String describeEnum(Object enumEntry) {
 class MatrixApi extends Api {
   /// The homeserver this client is communicating with.
   Uri? get homeserver => baseUri;
+
   set homeserver(Uri? uri) => baseUri = uri;
 
   /// This is the access token for the matrix client. When it is undefined, then
   /// the user needs to sign in first.
   String? get accessToken => bearerToken;
+
   set accessToken(String? token) => bearerToken = token;
 
   @override
diff --git a/lib/src/model/algorithm_types.dart b/lib/src/model/algorithm_types.dart
index 59144cf3..e4f8548b 100644
--- a/lib/src/model/algorithm_types.dart
+++ b/lib/src/model/algorithm_types.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/auth/authentication_data.dart b/lib/src/model/auth/authentication_data.dart
index 85d39767..53ea3ecf 100644
--- a/lib/src/model/auth/authentication_data.dart
+++ b/lib/src/model/auth/authentication_data.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -24,7 +23,7 @@
 
 class AuthenticationData {
   String type;
-  String?/*?*//*?*/ session;
+  String? /*?*/ /*?*/ session;
 
   AuthenticationData({required this.type, this.session});
 
@@ -34,7 +33,7 @@ class AuthenticationData {
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
-    if (type != null) data['type'] = type;
+    data['type'] = type;
     if (session != null) data['session'] = session;
     return data;
   }
diff --git a/lib/src/model/auth/authentication_identifier.dart b/lib/src/model/auth/authentication_identifier.dart
index 572932a0..ada4778a 100644
--- a/lib/src/model/auth/authentication_identifier.dart
+++ b/lib/src/model/auth/authentication_identifier.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,10 +21,10 @@
 * SOFTWARE.
 */
 
-import 'authentication_types.dart';
-import 'authentication_user_identifier.dart';
 import 'authentication_phone_identifier.dart';
 import 'authentication_third_party_identifier.dart';
+import 'authentication_types.dart';
+import 'authentication_user_identifier.dart';
 
 class AuthenticationIdentifier {
   String type;
diff --git a/lib/src/model/auth/authentication_password.dart b/lib/src/model/auth/authentication_password.dart
index b1066c2f..2b5cb13a 100644
--- a/lib/src/model/auth/authentication_password.dart
+++ b/lib/src/model/auth/authentication_password.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,11 +21,10 @@
 * SOFTWARE.
 */
 
-import 'authentication_user_identifier.dart';
-
 import 'authentication_data.dart';
 import 'authentication_identifier.dart';
 import 'authentication_types.dart';
+import 'authentication_user_identifier.dart';
 
 class AuthenticationPassword extends AuthenticationData {
   String? user;
@@ -37,7 +35,10 @@ class AuthenticationPassword extends AuthenticationData {
   AuthenticationIdentifier identifier;
 
   AuthenticationPassword(
-      {String? session, required this.password, this.user, required this.identifier})
+      {String? session,
+      required this.password,
+      this.user,
+      required this.identifier})
       : super(
           type: AuthenticationTypes.password,
           session: session,
diff --git a/lib/src/model/auth/authentication_phone_identifier.dart b/lib/src/model/auth/authentication_phone_identifier.dart
index 5e3c7779..e6eb8aa6 100644
--- a/lib/src/model/auth/authentication_phone_identifier.dart
+++ b/lib/src/model/auth/authentication_phone_identifier.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/auth/authentication_recaptcha.dart b/lib/src/model/auth/authentication_recaptcha.dart
index fdedf5b3..20c8d3c2 100644
--- a/lib/src/model/auth/authentication_recaptcha.dart
+++ b/lib/src/model/auth/authentication_recaptcha.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/auth/authentication_third_party_identifier.dart b/lib/src/model/auth/authentication_third_party_identifier.dart
index 94b55e28..2860dfdf 100644
--- a/lib/src/model/auth/authentication_third_party_identifier.dart
+++ b/lib/src/model/auth/authentication_third_party_identifier.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -29,7 +28,8 @@ class AuthenticationThirdPartyIdentifier extends AuthenticationIdentifier {
   String medium;
   String address;
 
-  AuthenticationThirdPartyIdentifier({required this.medium, required this.address})
+  AuthenticationThirdPartyIdentifier(
+      {required this.medium, required this.address})
       : super(type: AuthenticationIdentifierTypes.thirdParty);
 
   AuthenticationThirdPartyIdentifier.fromJson(Map<String, dynamic> json)
diff --git a/lib/src/model/auth/authentication_three_pid_creds.dart b/lib/src/model/auth/authentication_three_pid_creds.dart
index 2961ac56..8a20d904 100644
--- a/lib/src/model/auth/authentication_three_pid_creds.dart
+++ b/lib/src/model/auth/authentication_three_pid_creds.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -31,7 +30,8 @@ import 'authentication_data.dart';
 class AuthenticationThreePidCreds extends AuthenticationData {
   late List<ThreepidCreds> threepidCreds;
 
-  AuthenticationThreePidCreds({String? session, required String type, required this.threepidCreds})
+  AuthenticationThreePidCreds(
+      {String? session, required String type, required this.threepidCreds})
       : super(
           type: type,
           session: session,
@@ -65,13 +65,16 @@ class AuthenticationThreePidCreds extends AuthenticationData {
 }
 
 class ThreepidCreds {
-  String/*!*/ sid;
+  String /*!*/ sid;
   String clientSecret;
   String idServer;
   String idAccessToken;
 
   ThreepidCreds(
-      {required this.sid, required this.clientSecret, required this.idServer, required this.idAccessToken});
+      {required this.sid,
+      required this.clientSecret,
+      required this.idServer,
+      required this.idAccessToken});
 
   ThreepidCreds.fromJson(Map<String, dynamic> json)
       : sid = json['sid'],
diff --git a/lib/src/model/auth/authentication_token.dart b/lib/src/model/auth/authentication_token.dart
index 63233f4f..13749069 100644
--- a/lib/src/model/auth/authentication_token.dart
+++ b/lib/src/model/auth/authentication_token.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/auth/authentication_types.dart b/lib/src/model/auth/authentication_types.dart
index 00f13793..ea181e40 100644
--- a/lib/src/model/auth/authentication_types.dart
+++ b/lib/src/model/auth/authentication_types.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/auth/authentication_user_identifier.dart b/lib/src/model/auth/authentication_user_identifier.dart
index 974f7fee..9070dc48 100644
--- a/lib/src/model/auth/authentication_user_identifier.dart
+++ b/lib/src/model/auth/authentication_user_identifier.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/basic_event.dart b/lib/src/model/basic_event.dart
index 666fa516..5ea833f1 100644
--- a/lib/src/model/basic_event.dart
+++ b/lib/src/model/basic_event.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/basic_event_with_sender.dart b/lib/src/model/basic_event_with_sender.dart
index 4b6114a7..6618fc5a 100644
--- a/lib/src/model/basic_event_with_sender.dart
+++ b/lib/src/model/basic_event_with_sender.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -27,7 +26,11 @@ import 'basic_event.dart';
 class BasicEventWithSender extends BasicEvent {
   String senderId;
 
-  BasicEventWithSender();
+  BasicEventWithSender(
+      {required String type,
+      required Map<String, dynamic> content,
+      required this.senderId})
+      : super(type: type, content: content);
 
   BasicEventWithSender.fromJson(Map<String, dynamic> json)
       : senderId = json['sender'],
diff --git a/lib/src/model/basic_room_event.dart b/lib/src/model/basic_room_event.dart
index 66eff7d8..0e416483 100644
--- a/lib/src/model/basic_room_event.dart
+++ b/lib/src/model/basic_room_event.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/event_types.dart b/lib/src/model/event_types.dart
index 19623f5d..d5adc9ac 100644
--- a/lib/src/model/event_types.dart
+++ b/lib/src/model/event_types.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 *
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -68,6 +67,7 @@ abstract class EventTypes {
   static const String CrossSigningMasterKey = 'm.cross_signing.master';
   static const String MegolmBackup = 'm.megolm_backup.v1';
   static const String SecretStorageDefaultKey = 'm.secret_storage.default_key';
+
   static String secretStorageKey(String keyId) => 'm.secret_storage.key.$keyId';
 
   // Spaces
diff --git a/lib/src/model/events/forwarded_room_key_content.dart b/lib/src/model/events/forwarded_room_key_content.dart
index fb8ca523..b4ec3232 100644
--- a/lib/src/model/events/forwarded_room_key_content.dart
+++ b/lib/src/model/events/forwarded_room_key_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,8 +21,8 @@
 * SOFTWARE.
 */
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 import 'room_key_content.dart';
 
 extension ForwardedRoomKeyContentBasicEventExtension on BasicEvent {
@@ -35,12 +34,13 @@ class ForwardedRoomKeyContent extends RoomKeyContent {
   String senderKey;
   String senderClaimedEd25519Key;
   List<String> forwardingCurve25519KeyChain;
+
   ForwardedRoomKeyContent.fromJson(Map<String, dynamic> json)
-      : senderKey = json.tryGet<String>('sender_key', ''),
+      : senderKey = json.tryGet('sender_key') ?? '',
         senderClaimedEd25519Key =
-            json.tryGet<String>('sender_claimed_ed25519_key', ''),
+            json.tryGet('sender_claimed_ed25519_key') ?? '',
         forwardingCurve25519KeyChain =
-            json.tryGetList<String>('forwarding_curve25519_key_chain', []),
+            json.tryGetList('forwarding_curve25519_key_chain') ?? [],
         super.fromJson(json);
 
   @override
diff --git a/lib/src/model/events/olm_plaintext_payload.dart b/lib/src/model/events/olm_plaintext_payload.dart
index 69a6d0e8..5f67ca1b 100644
--- a/lib/src/model/events/olm_plaintext_payload.dart
+++ b/lib/src/model/events/olm_plaintext_payload.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -43,12 +42,12 @@ class OlmPlaintextPayload {
 
   factory OlmPlaintextPayload.fromJson(Map<String, dynamic> json) =>
       OlmPlaintextPayload(
-        sender: json.tryGet<String>('sender'),
-        type: json.tryGet<String>('type'),
-        content: json.tryGetMap<String, dynamic>('content'),
-        recipient: json.tryGet<String>('recipient'),
-        recipientKeys: json.tryGetMap<String, String>('recipient_keys'),
-        keys: json.tryGetMap<String, String>('keys'),
+        sender: json.tryGet('sender'),
+        type: json.tryGet('type'),
+        content: json.tryGetMap('content'),
+        recipient: json.tryGet('recipient'),
+        recipientKeys: json.tryGetMap('recipient_keys'),
+        keys: json.tryGetMap('keys'),
       );
 
   Map<String, dynamic> toJson() {
diff --git a/lib/src/model/events/room_encrypted_content.dart b/lib/src/model/events/room_encrypted_content.dart
index 3608621a..e062f77f 100644
--- a/lib/src/model/events/room_encrypted_content.dart
+++ b/lib/src/model/events/room_encrypted_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -24,8 +23,8 @@
 
 import 'package:matrix_api_lite/src/utils/logs.dart';
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 
 extension RoomEncryptedContentBasicEventExtension on BasicEvent {
   RoomEncryptedContent get parsedRoomEncryptedContent =>
@@ -41,18 +40,14 @@ class RoomEncryptedContent {
   Map<String, CiphertextInfo>? ciphertextOlm;
 
   RoomEncryptedContent.fromJson(Map<String, dynamic> json)
-      : algorithm = json.tryGet<String>('algorithm', ''),
-        senderKey = json.tryGet<String>('sender_key', ''),
-        deviceId = json.tryGet<String>('device_id'),
-        sessionId = json.tryGet<String>('session_id'),
-        ciphertextMegolm = json['ciphertext'] is String
-            ? json.tryGet<String>('ciphertext')
-            : null,
-        ciphertextOlm = json['ciphertext'] is Map<String, dynamic>
-            ? json
-                .tryGet<Map<String, dynamic>>('ciphertext')
-                ?.map((k, v) => MapEntry(k, CiphertextInfo.fromJson(v)))
-            : null;
+      : algorithm = json.tryGet('algorithm') ?? '',
+        senderKey = json.tryGet('sender_key') ?? '',
+        deviceId = json.tryGet('device_id'),
+        sessionId = json.tryGet('session_id'),
+        ciphertextMegolm = json.tryGet('ciphertext'),
+        ciphertextOlm = json
+            .tryGet<Map<String, dynamic>>('ciphertext')
+            ?.map((k, v) => MapEntry(k, CiphertextInfo.fromJson(v)));
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
@@ -68,7 +63,8 @@ class RoomEncryptedContent {
       data['ciphertext'] = ciphertextMegolm;
     }
     if (ciphertextOlm != null) {
-      data['ciphertext'] = ciphertextOlm!.map((k, v) => MapEntry(k, v.toJson()));
+      data['ciphertext'] =
+          ciphertextOlm!.map((k, v) => MapEntry(k, v.toJson()));
       if (ciphertextMegolm != null) {
         Logs().wtf(
             'ciphertextOlm and ciphertextMegolm are both set, which should never happen!');
@@ -83,17 +79,13 @@ class CiphertextInfo {
   int type;
 
   CiphertextInfo.fromJson(Map<String, dynamic> json)
-      : body = json.tryGet<String>('body'),
-        type = json.tryGet<int>('type');
+      : body = json['body'],
+        type = json['type'];
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
-    if (body != null) {
-      data['body'] = body;
-    }
-    if (type != null) {
-      data['type'] = type;
-    }
+    data['body'] = body;
+    data['type'] = type;
     return data;
   }
 }
diff --git a/lib/src/model/events/room_encryption_content.dart b/lib/src/model/events/room_encryption_content.dart
index c639ba67..b88db983 100644
--- a/lib/src/model/events/room_encryption_content.dart
+++ b/lib/src/model/events/room_encryption_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,8 +21,8 @@
 * SOFTWARE.
 */
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 
 extension RoomEncryptionContentBasicEventExtension on BasicEvent {
   RoomEncryptionContent get parsedRoomEncryptionContent =>
@@ -36,9 +35,9 @@ class RoomEncryptionContent {
   int? rotationPeriodMsgs;
 
   RoomEncryptionContent.fromJson(Map<String, dynamic> json)
-      : algorithm = json.tryGet<String>('algorithm', ''),
-        rotationPeriodMs = json.tryGet<int?>('rotation_period_ms'),
-        rotationPeriodMsgs = json.tryGet<int?>('rotation_period_msgs');
+      : algorithm = json.tryGet('algorithm') ?? '',
+        rotationPeriodMs = json.tryGet('rotation_period_ms'),
+        rotationPeriodMsgs = json.tryGet('rotation_period_msgs');
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
diff --git a/lib/src/model/events/room_key_content.dart b/lib/src/model/events/room_key_content.dart
index 4149ffad..e179e662 100644
--- a/lib/src/model/events/room_key_content.dart
+++ b/lib/src/model/events/room_key_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,8 +21,8 @@
 * SOFTWARE.
 */
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 
 extension RoomKeyContentBasicEventExtension on BasicEvent {
   RoomKeyContent get parsedRoomKeyContent => RoomKeyContent.fromJson(content);
@@ -35,13 +34,17 @@ class RoomKeyContent {
   String sessionId;
   String sessionKey;
 
-  RoomKeyContent();
+  RoomKeyContent(
+      {required this.algorithm,
+      required this.roomId,
+      required this.sessionId,
+      required this.sessionKey});
 
   RoomKeyContent.fromJson(Map<String, dynamic> json)
-      : algorithm = json.tryGet<String>('algorithm', ''),
-        roomId = json.tryGet<String>('room_id', ''),
-        sessionId = json.tryGet<String>('session_id', ''),
-        sessionKey = json.tryGet<String>('session_key', '');
+      : algorithm = json.tryGet('algorithm') ?? '',
+        roomId = json.tryGet('room_id') ?? '',
+        sessionId = json.tryGet('session_id') ?? '',
+        sessionKey = json.tryGet('session_key') ?? '';
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
diff --git a/lib/src/model/events/room_key_request_content.dart b/lib/src/model/events/room_key_request_content.dart
index 1a7e6871..394d8233 100644
--- a/lib/src/model/events/room_key_request_content.dart
+++ b/lib/src/model/events/room_key_request_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,8 +21,8 @@
 * SOFTWARE.
 */
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 
 extension RoomKeyRequestContentBasicEventExtension on BasicEvent {
   RoomKeyRequestContent get parsedRoomKeyRequestContent =>
@@ -37,11 +36,11 @@ class RoomKeyRequestContent {
   String requestId;
 
   RoomKeyRequestContent.fromJson(Map<String, dynamic> json)
-      : body = RequestedKeyInfo.fromJson(
+      : body = ((x) => x != null ? RequestedKeyInfo.fromJson(x) : null)(
             json.tryGet<Map<String, dynamic>>('body')),
-        action = json.tryGet<String>('action', ''),
-        requestingDeviceId = json.tryGet<String>('requesting_device_id', ''),
-        requestId = json.tryGet<String>('request_id', '');
+        action = json.tryGet<String>('action') ?? '',
+        requestingDeviceId = json.tryGet<String>('requesting_device_id') ?? '',
+        requestId = json.tryGet<String>('request_id') ?? '';
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
@@ -59,17 +58,17 @@ class RequestedKeyInfo {
   String sessionId;
   String senderKey;
 
-  RequestedKeyInfo();
+  RequestedKeyInfo(
+      {required this.algorithm,
+      required this.roomId,
+      required this.sessionId,
+      required this.senderKey});
 
-  factory RequestedKeyInfo.fromJson(Map<String, dynamic> json) {
-    if (json == null) return null;
-    final requestKeyInfo = RequestedKeyInfo();
-    requestKeyInfo.algorithm = json.tryGet<String>('algorithm', '');
-    requestKeyInfo.roomId = json.tryGet<String>('room_id', '');
-    requestKeyInfo.sessionId = json.tryGet<String>('session_id', '');
-    requestKeyInfo.senderKey = json.tryGet<String>('sender_key', '');
-    return requestKeyInfo;
-  }
+  RequestedKeyInfo.fromJson(Map<String, dynamic> json)
+      : algorithm = json.tryGet('algorithm') ?? '',
+        roomId = json.tryGet('room_id') ?? '',
+        sessionId = json.tryGet('session_id') ?? '',
+        senderKey = json.tryGet('sender_key') ?? '';
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
diff --git a/lib/src/model/events/secret_storage_default_key_content.dart b/lib/src/model/events/secret_storage_default_key_content.dart
index 389795d0..46394fbf 100644
--- a/lib/src/model/events/secret_storage_default_key_content.dart
+++ b/lib/src/model/events/secret_storage_default_key_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,8 +21,8 @@
 * SOFTWARE.
 */
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 
 extension SecretStorageDefaultKeyContentBasicEventExtension on BasicEvent {
   SecretStorageDefaultKeyContent get parsedSecretStorageDefaultKeyContent =>
@@ -31,9 +30,10 @@ extension SecretStorageDefaultKeyContentBasicEventExtension on BasicEvent {
 }
 
 class SecretStorageDefaultKeyContent {
-  String key;
+  //TODO: Required by spec, we should require it here and make sure to catch it everywhere
+  String? key;
 
-  SecretStorageDefaultKeyContent();
+  SecretStorageDefaultKeyContent({required this.key});
 
   SecretStorageDefaultKeyContent.fromJson(Map<String, dynamic> json)
       : key = json.tryGet<String>('key');
diff --git a/lib/src/model/events/secret_storage_key_content.dart b/lib/src/model/events/secret_storage_key_content.dart
index 8e10a182..b6542bac 100644
--- a/lib/src/model/events/secret_storage_key_content.dart
+++ b/lib/src/model/events/secret_storage_key_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,8 +21,8 @@
 * SOFTWARE.
 */
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 
 extension SecretStorageKeyContentBasicEventExtension on BasicEvent {
   SecretStorageKeyContent get parsedSecretStorageKeyContent =>
@@ -42,9 +41,9 @@ class SecretStorageKeyContent {
       : passphrase = json['passphrase'] is Map<String, dynamic>
             ? PassphraseInfo.fromJson(json['passphrase'])
             : null,
-        iv = json.tryGet<String?>('iv'),
-        mac = json.tryGet<String?>('mac'),
-        algorithm = json.tryGet<String?>('algorithm');
+        iv = json.tryGet('iv'),
+        mac = json.tryGet('mac'),
+        algorithm = json.tryGet('algorithm');
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
@@ -57,24 +56,30 @@ class SecretStorageKeyContent {
 }
 
 class PassphraseInfo {
-  String algorithm;
-  String salt;
-  int iterations;
+  //TODO: algorithm, salt, iterations are required by spec,
+  //TODO: we should require it here and make sure to catch it everywhere
+  String? algorithm;
+  String? salt;
+  int? iterations;
   int? bits;
 
-  PassphraseInfo();
+  PassphraseInfo(
+      {required this.algorithm,
+      required this.salt,
+      required this.iterations,
+      this.bits});
 
   PassphraseInfo.fromJson(Map<String, dynamic> json)
-      : algorithm = json.tryGet<String>('algorithm'),
-        salt = json.tryGet<String>('salt'),
-        iterations = json.tryGet<int>('iterations'),
+      : algorithm = json.tryGet('algorithm'),
+        salt = json.tryGet('salt'),
+        iterations = json.tryGet('iterations'),
         bits = json.tryGet<int>('bits');
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
-    if (algorithm != null) data['algorithm'] = algorithm;
-    if (salt != null) data['salt'] = salt;
-    if (iterations != null) data['iterations'] = iterations;
+    data['algorithm'] = algorithm;
+    data['salt'] = salt;
+    data['iterations'] = iterations;
     if (bits != null) data['bits'] = bits;
     return data;
   }
diff --git a/lib/src/model/events/tombstone_content.dart b/lib/src/model/events/tombstone_content.dart
index 93a8221f..18804448 100644
--- a/lib/src/model/events/tombstone_content.dart
+++ b/lib/src/model/events/tombstone_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,8 +21,8 @@
 * SOFTWARE.
 */
 
-import '../basic_event.dart';
 import '../../utils/try_get_map_extension.dart';
+import '../basic_event.dart';
 
 extension TombstoneContentBasicEventExtension on BasicEvent {
   TombstoneContent get parsedTombstoneContent =>
@@ -35,8 +34,8 @@ class TombstoneContent {
   String replacementRoom;
 
   TombstoneContent.fromJson(Map<String, dynamic> json)
-      : body = json.tryGet<String>('body', ''),
-        replacementRoom = json.tryGet<String>('replacement_room', '');
+      : body = json.tryGet('body') ?? '',
+        replacementRoom = json.tryGet('replacement_room') ?? '';
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
diff --git a/lib/src/model/events_sync_update.dart b/lib/src/model/events_sync_update.dart
index a93ee5b3..2f35ac74 100644
--- a/lib/src/model/events_sync_update.dart
+++ b/lib/src/model/events_sync_update.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/matrix_connection_exception.dart b/lib/src/model/matrix_connection_exception.dart
index 96d12af9..97194f64 100644
--- a/lib/src/model/matrix_connection_exception.dart
+++ b/lib/src/model/matrix_connection_exception.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -25,6 +24,7 @@
 class MatrixConnectionException implements Exception {
   final dynamic original;
   final StackTrace stackTrace;
+
   MatrixConnectionException(this.original, this.stackTrace);
 
   @override
diff --git a/lib/src/model/matrix_event.dart b/lib/src/model/matrix_event.dart
index b54856db..516f4b35 100644
--- a/lib/src/model/matrix_event.dart
+++ b/lib/src/model/matrix_event.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,18 +21,33 @@
 * SOFTWARE.
 */
 
-import 'stripped_state_event.dart';
 import '../utils/map_copy_extension.dart';
+import 'stripped_state_event.dart';
 
 class MatrixEvent extends StrippedStateEvent {
   String eventId;
   String? roomId;
-  late DateTime originServerTs;
+  DateTime originServerTs;
   Map<String, dynamic>? unsigned;
   Map<String, dynamic>? prevContent;
   String? redacts;
 
-  MatrixEvent();
+  MatrixEvent({
+    required String type,
+    required Map<String, dynamic> content,
+    required String senderId,
+    String? stateKey,
+    required this.eventId,
+    this.roomId,
+    required this.originServerTs,
+    this.unsigned,
+    this.prevContent,
+    this.redacts,
+  }) : super(
+            type: type,
+            content: content,
+            senderId: senderId,
+            stateKey: stateKey);
 
   MatrixEvent.fromJson(Map<String, dynamic> json)
       : eventId = json['event_id'],
diff --git a/lib/src/model/matrix_exception.dart b/lib/src/model/matrix_exception.dart
index f2a03e24..3e7ef751 100644
--- a/lib/src/model/matrix_exception.dart
+++ b/lib/src/model/matrix_exception.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -62,7 +61,9 @@ class MatrixException implements Exception {
   /// The frozen request which triggered this Error
   http.Response? response;
 
-  MatrixException(Response this.response) : raw = json.decode(response.body);
+  MatrixException(http.Response this.response)
+      : raw = json.decode(response.body);
+
   MatrixException.fromJson(Map<String, dynamic> content) : raw = content;
 
   @override
@@ -87,7 +88,7 @@ class MatrixException implements Exception {
   /// For each endpoint, a server offers one or more 'flows' that the client can use
   /// to authenticate itself. Each flow comprises a series of stages. If this request
   /// doesn't need additional authentication, then this is null.
-  List<AuthenticationFlow>?/*?*/ get authenticationFlows {
+  List<AuthenticationFlow>? get authenticationFlows {
     if (!raw.containsKey('flows') || !(raw['flows'] is List)) return null;
     return (raw['flows'] as List)
         .map((flow) => flow['stages'])
@@ -110,5 +111,6 @@ class MatrixException implements Exception {
 /// to authenticate itself. Each flow comprises a series of stages
 class AuthenticationFlow {
   final List<String> stages;
+
   const AuthenticationFlow(this.stages);
 }
diff --git a/lib/src/model/matrix_keys.dart b/lib/src/model/matrix_keys.dart
index 2ad89ed1..01c0538a 100644
--- a/lib/src/model/matrix_keys.dart
+++ b/lib/src/model/matrix_keys.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -24,15 +23,16 @@
 
 import '../utils/map_copy_extension.dart';
 
-class MatrixSignableKey {
+abstract class MatrixSignableKey {
   String userId;
-  String? identifier;
+
+  String? get identifier;
+
   Map<String, String> keys;
   Map<String, Map<String, String>>? signatures;
   Map<String, dynamic>? unsigned;
 
-  MatrixSignableKey(this.userId, this.identifier, this.keys, this.signatures,
-      {this.unsigned});
+  MatrixSignableKey(this.userId, this.keys, this.signatures, {this.unsigned});
 
   // This object is used for signing so we need the raw json too
   Map<String, dynamic>? _json;
@@ -65,6 +65,7 @@ class MatrixSignableKey {
 
 class MatrixCrossSigningKey extends MatrixSignableKey {
   List<String> usage;
+
   String? get publicKey => identifier;
 
   MatrixCrossSigningKey(
@@ -73,14 +74,15 @@ class MatrixCrossSigningKey extends MatrixSignableKey {
     Map<String, String> keys,
     Map<String, Map<String, String>> signatures, {
     Map<String, dynamic>? unsigned,
-  }) : super(userId, keys?.values?.first, keys, signatures, unsigned: unsigned);
+  }) : super(userId, keys, signatures, unsigned: unsigned);
+
+  @override
+  String? get identifier => keys.values.first;
 
   @override
   MatrixCrossSigningKey.fromJson(Map<String, dynamic> json)
-      : super.fromJson(json) {
-    usage = List<String>.from(json['usage']);
-    identifier = keys?.values?.first;
-  }
+      : usage = List<String>.from(json['usage']),
+        super.fromJson(json);
 
   @override
   Map<String, dynamic> toJson() {
@@ -91,25 +93,29 @@ class MatrixCrossSigningKey extends MatrixSignableKey {
 }
 
 class MatrixDeviceKeys extends MatrixSignableKey {
-  String get deviceId => identifier!;
+  String deviceId;
   List<String> algorithms;
+
   String? get deviceDisplayName =>
       unsigned != null ? unsigned!['device_display_name'] : null;
 
   MatrixDeviceKeys(
     String userId,
-    String deviceId,
+    this.deviceId,
     this.algorithms,
     Map<String, String> keys,
     Map<String, Map<String, String>> signatures, {
     Map<String, dynamic>? unsigned,
-  }) : super(userId, deviceId, keys, signatures, unsigned: unsigned);
+  }) : super(userId, keys, signatures, unsigned: unsigned);
 
   @override
-  MatrixDeviceKeys.fromJson(Map<String, dynamic> json) : super.fromJson(json) {
-    identifier = json['device_id'];
-    algorithms = json['algorithms'].cast<String>();
-  }
+  String? get identifier => deviceId;
+
+  @override
+  MatrixDeviceKeys.fromJson(Map<String, dynamic> json)
+      : algorithms = json['algorithms'].cast<String>(),
+        deviceId = json['device_id'],
+        super.fromJson(json);
 
   @override
   Map<String, dynamic> toJson() {
diff --git a/lib/src/model/message_types.dart b/lib/src/model/message_types.dart
index e6cbc443..d6745350 100644
--- a/lib/src/model/message_types.dart
+++ b/lib/src/model/message_types.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/presence.dart b/lib/src/model/presence.dart
index 4874ea54..73848c2e 100644
--- a/lib/src/model/presence.dart
+++ b/lib/src/model/presence.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/presence_content.dart b/lib/src/model/presence_content.dart
index 0df3f0c2..edf9a1de 100644
--- a/lib/src/model/presence_content.dart
+++ b/lib/src/model/presence_content.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/request_token_response.dart b/lib/src/model/request_token_response.dart
index 46f24e5c..4be5d726 100644
--- a/lib/src/model/request_token_response.dart
+++ b/lib/src/model/request_token_response.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/room_creation_types.dart b/lib/src/model/room_creation_types.dart
index be7b75d9..703f0ce1 100644
--- a/lib/src/model/room_creation_types.dart
+++ b/lib/src/model/room_creation_types.dart
@@ -1,4 +1,3 @@
-
 abstract class RoomCreationTypes {
   static const String mSpace = 'm.space';
 }
diff --git a/lib/src/model/room_keys_keys.dart b/lib/src/model/room_keys_keys.dart
index b285c454..39df80b4 100644
--- a/lib/src/model/room_keys_keys.dart
+++ b/lib/src/model/room_keys_keys.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -53,9 +52,7 @@ class RoomKeysSingleKey {
 class RoomKeysRoom {
   Map<String, RoomKeysSingleKey> sessions;
 
-  RoomKeysRoom({required this.sessions}) {
-    sessions ??= <String, RoomKeysSingleKey>{};
-  }
+  RoomKeysRoom({required this.sessions});
 
   RoomKeysRoom.fromJson(Map<String, dynamic> json)
       : sessions = (json['sessions'] as Map)
diff --git a/lib/src/model/room_summary.dart b/lib/src/model/room_summary.dart
index 74dded00..1947d829 100644
--- a/lib/src/model/room_summary.dart
+++ b/lib/src/model/room_summary.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -26,6 +25,7 @@ class RoomSummary {
   List<String>? mHeroes;
   int? mJoinedMemberCount;
   int? mInvitedMemberCount;
+
   RoomSummary.fromJson(Map<String, dynamic> json)
       : mHeroes = json['m.heroes'] != null
             ? List<String>.from(json['m.heroes'])
diff --git a/lib/src/model/room_types.dart b/lib/src/model/room_types.dart
index 7dbcf0f5..ba551ae9 100644
--- a/lib/src/model/room_types.dart
+++ b/lib/src/model/room_types.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 *
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/stripped_state_event.dart b/lib/src/model/stripped_state_event.dart
index cb8f914d..20bd4927 100644
--- a/lib/src/model/stripped_state_event.dart
+++ b/lib/src/model/stripped_state_event.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -27,7 +26,13 @@ import 'basic_event_with_sender.dart';
 class StrippedStateEvent extends BasicEventWithSender {
   String? stateKey;
 
-  StrippedStateEvent();
+  StrippedStateEvent(
+      {required String type,
+      required Map<String, dynamic> content,
+      required String senderId,
+      this.stateKey})
+      : super(type: type, content: content, senderId: senderId);
+
   StrippedStateEvent.fromJson(Map<String, dynamic> json)
       : stateKey = json['state_key'],
         super.fromJson(json);
diff --git a/lib/src/model/supported_protocol.dart b/lib/src/model/supported_protocol.dart
index 32cba75c..0f1fcf50 100644
--- a/lib/src/model/supported_protocol.dart
+++ b/lib/src/model/supported_protocol.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -45,9 +44,7 @@ class SupportedProtocol {
     data['location_fields'] = locationFields;
     data['icon'] = icon;
     data['field_types'] = fieldTypes.map((k, v) => MapEntry(k, v.toJson()));
-
     data['instances'] = instances.map((v) => v.toJson()).toList();
-
     return data;
   }
 }
@@ -56,10 +53,9 @@ class ProtocolFieldType {
   String regexp;
   String placeholder;
 
-  ProtocolFieldType.fromJson(Map<String, dynamic> json) {
-    regexp = json['regexp'];
-    placeholder = json['placeholder'];
-  }
+  ProtocolFieldType.fromJson(Map<String, dynamic> json)
+      : regexp = json['regexp'],
+        placeholder = json['placeholder'];
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
@@ -75,12 +71,11 @@ class ProtocolInstance {
   String? icon;
   dynamic fields;
 
-  ProtocolInstance.fromJson(Map<String, dynamic> json) {
-    networkId = json['network_id'];
-    desc = json['desc'];
-    icon = json['icon'];
-    fields = json['fields'];
-  }
+  ProtocolInstance.fromJson(Map<String, dynamic> json)
+      : networkId = json['network_id'],
+        desc = json['desc'],
+        icon = json['icon'],
+        fields = json['fields'];
 
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
diff --git a/lib/src/model/sync_update.dart b/lib/src/model/sync_update.dart
index 5b93d1ef..878b9343 100644
--- a/lib/src/model/sync_update.dart
+++ b/lib/src/model/sync_update.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 *
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -40,7 +39,7 @@ class SyncUpdate {
   Map<String, int>? deviceOneTimeKeysCount;
   List<String>? deviceUnusedFallbackKeyTypes;
 
-  SyncUpdate();
+  SyncUpdate({required this.nextBatch});
 
   SyncUpdate.fromJson(Map<String, dynamic> json)
       : nextBatch = json['next_batch'],
@@ -136,6 +135,7 @@ class RoomsUpdate {
             .map((k, v) => MapEntry(k, LeftRoomUpdate.fromJson(v)))
         : null;
   }
+
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
     if (join != null) {
@@ -224,6 +224,7 @@ class JoinedRoomUpdate extends SyncRoomUpdate {
 
 class InvitedRoomUpdate extends SyncRoomUpdate {
   List<StrippedStateEvent>? inviteState;
+
   InvitedRoomUpdate.fromJson(Map<String, dynamic> json) {
     inviteState =
         (json['invite_state'] != null && json['invite_state']['events'] != null)
@@ -232,6 +233,7 @@ class InvitedRoomUpdate extends SyncRoomUpdate {
                 .toList()
             : null;
   }
+
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
     if (inviteState != null) {
@@ -266,6 +268,7 @@ class LeftRoomUpdate extends SyncRoomUpdate {
                 .toList()
             : null;
   }
+
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
     if (state != null) {
@@ -318,10 +321,12 @@ class TimelineUpdate {
 class UnreadNotificationCounts {
   int? highlightCount;
   int? notificationCount;
+
   UnreadNotificationCounts.fromJson(Map<String, dynamic> json) {
     highlightCount = json['highlight_count'];
     notificationCount = json['notification_count'];
   }
+
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
     if (highlightCount != null) {
@@ -337,10 +342,12 @@ class UnreadNotificationCounts {
 class DeviceListsUpdate {
   List<String>? changed;
   List<String>? left;
+
   DeviceListsUpdate.fromJson(Map<String, dynamic> json) {
     changed = List<String>.from(json['changed'] ?? []);
     left = List<String>.from(json['left'] ?? []);
   }
+
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
     if (changed != null) {
diff --git a/lib/src/model/third_party_location.dart b/lib/src/model/third_party_location.dart
index fb834daf..a2271f9b 100644
--- a/lib/src/model/third_party_location.dart
+++ b/lib/src/model/third_party_location.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/third_party_user.dart b/lib/src/model/third_party_user.dart
index e230e4ab..a4289b2a 100644
--- a/lib/src/model/third_party_user.dart
+++ b/lib/src/model/third_party_user.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/model/upload_key_signatures_response.dart b/lib/src/model/upload_key_signatures_response.dart
index 94f3255f..38bf3774 100644
--- a/lib/src/model/upload_key_signatures_response.dart
+++ b/lib/src/model/upload_key_signatures_response.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/utils/logs.dart b/lib/src/utils/logs.dart
index 105319a3..37852945 100644
--- a/lib/src/utils/logs.dart
+++ b/lib/src/utils/logs.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/utils/map_copy_extension.dart b/lib/src/utils/map_copy_extension.dart
index d2b89720..2cf95989 100644
--- a/lib/src/utils/map_copy_extension.dart
+++ b/lib/src/utils/map_copy_extension.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 *
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/lib/src/utils/try_get_map_extension.dart b/lib/src/utils/try_get_map_extension.dart
index 0024aa12..d768a24d 100644
--- a/lib/src/utils/try_get_map_extension.dart
+++ b/lib/src/utils/try_get_map_extension.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -25,60 +24,45 @@
 import 'logs.dart';
 
 extension TryGetMapExtension on Map<String, dynamic> {
-  T tryGet<T>(String key, [T fallbackValue]) {
+  T? tryGet<T extends Object>(String key) {
     final value = this[key];
     if (value != null && !(value is T)) {
       Logs().w(
           'Expected "${T.runtimeType}" in event content for the Key "$key" but got "${value.runtimeType}".');
-      return fallbackValue;
-    }
-    if (value == null && fallbackValue != null) {
-      Logs().w(
-          'Required field in event content for the Key "$key" is null. Set to "$fallbackValue".');
-      return fallbackValue;
+      return null;
     }
     return value;
   }
 
-  List<T> tryGetList<T>(String key, [List<T> fallbackValue]) {
+  List<T>? tryGetList<T>(String key) {
     final value = this[key];
     if (value != null && !(value is List)) {
       Logs().w(
           'Expected "List<${T.runtimeType}>" in event content for the key "$key" but got "${value.runtimeType}".');
-      return fallbackValue;
-    }
-    if (value == null && fallbackValue != null) {
-      Logs().w(
-          'Required field in event content for the key "$key" is null. Set to "$fallbackValue".');
-      return fallbackValue;
+      return null;
     }
     try {
       return (value as List).cast<T>();
     } catch (_) {
       Logs().w(
           'Unable to create "List<${T.runtimeType}>" in event content for the key "$key"');
-      return fallbackValue;
+      return null;
     }
   }
 
-  Map<A, B> tryGetMap<A, B>(String key, [Map<A, B> fallbackValue]) {
+  Map<A, B>? tryGetMap<A, B>(String key) {
     final value = this[key];
     if (value != null && !(value is Map)) {
       Logs().w(
           'Expected "Map<${A.runtimeType},${B.runtimeType}>" in event content for the key "$key" but got "${value.runtimeType}".');
-      return fallbackValue;
-    }
-    if (value == null && fallbackValue != null) {
-      Logs().w(
-          'Required field in event content for the key "$key" is null. Set to "$fallbackValue".');
-      return fallbackValue;
+      return null;
     }
     try {
       return (value as Map).cast<A, B>();
     } catch (_) {
       Logs().w(
           'Unable to create "Map<${A.runtimeType},${B.runtimeType}>" in event content for the key "$key"');
-      return fallbackValue;
+      return null;
     }
   }
 }
diff --git a/lib/src/values.dart b/lib/src/values.dart
index b7f1c0c5..aa4f66ac 100644
--- a/lib/src/values.dart
+++ b/lib/src/values.dart
@@ -14,6 +14,7 @@ class TagType {
   static final favourite = 'm.favourite';
   static final lowPriority = 'm.lowpriority';
   static final serverNotice = 'm.server_notice';
+
   static bool isValid(String tag) => tag.startsWith('m.')
       ? [favourite, lowPriority, serverNotice].contains(tag)
       : true;
diff --git a/test/event_content_test.dart b/test/event_content_test.dart
index d7f79670..82099ac7 100644
--- a/test/event_content_test.dart
+++ b/test/event_content_test.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
@@ -22,9 +21,10 @@
 * SOFTWARE.
 */
 
+import 'dart:convert';
+
 import 'package:matrix_api_lite/matrix_api_lite.dart';
 import 'package:test/test.dart';
-import 'dart:convert';
 
 void main() {
   group('Event Content tests', () {
diff --git a/test/map_copy_extension_test.dart b/test/map_copy_extension_test.dart
index f67b60fc..329771d9 100644
--- a/test/map_copy_extension_test.dart
+++ b/test/map_copy_extension_test.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 *
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
diff --git a/test/matrix_api_test.dart b/test/matrix_api_test.dart
index 97b454e4..54a8f0a8 100644
--- a/test/matrix_api_test.dart
+++ b/test/matrix_api_test.dart
@@ -1,18 +1,17 @@
-
 /* MIT License
-* 
+*
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH
-* 
+*
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
-* 
+*
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
-* 
+*
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
@@ -23,6 +22,7 @@
 */
 
 import 'dart:typed_data';
+
 import 'package:matrix_api_lite/fake_matrix_api.dart';
 import 'package:matrix_api_lite/matrix_api_lite.dart';
 import 'package:test/test.dart';
@@ -60,8 +60,8 @@ void main() {
         'session': 'xxxxxxyz',
         'completed': ['example.type.foo']
       });
-      expect(
-          exception.authenticationFlows!.first.stages.first, 'example.type.foo');
+      expect(exception.authenticationFlows!.first.stages.first,
+          'example.type.foo');
       expect(exception.authenticationParams!['example.type.baz'],
           {'example_key': 'foobar'});
       expect(exception.session, 'xxxxxxyz');
@@ -111,10 +111,8 @@ void main() {
         expect((exception as MatrixException).errcode, 'M_FORBIDDEN');
         expect(exception.error, MatrixError.M_FORBIDDEN);
         expect(exception.errorMessage, 'Blabla');
-        expect(exception.requireAdditionalAuthentication,
-            false);
-        expect(
-            exception.toString(), 'M_FORBIDDEN: Blabla');
+        expect(exception.requireAdditionalAuthentication, false);
+        expect(exception.toString(), 'M_FORBIDDEN: Blabla');
         error = true;
       }
       expect(error, true);
@@ -146,10 +144,10 @@ void main() {
     });
     test('getLoginTypes', () async {
       matrixApi.homeserver = Uri.parse('https://fakeserver.notexisting');
-      final loginTypes = await (matrixApi.getLoginFlows() as FutureOr<List<LoginFlow>>);
-      expect(loginTypes.first.type, 'm.login.password');
+      final loginTypes = await matrixApi.getLoginFlows();
+      expect(loginTypes?.first.type, 'm.login.password');
       expect(FakeMatrixApi.api['GET']!['/client/r0/login']({}),
-          {'flows': loginTypes.map((x) => x.toJson()).toList()});
+          {'flows': loginTypes?.map((x) => x.toJson()).toList()});
       matrixApi.homeserver = null;
     });
     test('login', () async {
@@ -194,8 +192,8 @@ void main() {
         idAccessToken: '1234',
       );
       expect(
-          FakeMatrixApi.api['POST']!
-              ['/client/r0/register/email/requestToken']({}),
+          FakeMatrixApi
+              .api['POST']!['/client/r0/register/email/requestToken']({}),
           response.toJson());
       matrixApi.homeserver = matrixApi.accessToken = null;
     });
@@ -212,8 +210,8 @@ void main() {
         idAccessToken: '1234',
       );
       expect(
-          FakeMatrixApi.api['POST']!
-              ['/client/r0/register/email/requestToken']({}),
+          FakeMatrixApi
+              .api['POST']!['/client/r0/register/email/requestToken']({}),
           response.toJson());
       matrixApi.homeserver = matrixApi.accessToken = null;
     });
@@ -281,9 +279,9 @@ void main() {
     test('getThirdPartyIdentifiers', () async {
       matrixApi.homeserver = Uri.parse('https://fakeserver.notexisting');
       matrixApi.accessToken = '1234';
-      final response = await (matrixApi.getAccount3PIDs() as FutureOr<List<ThirdPartyIdentifier>>);
+      final response = await matrixApi.getAccount3PIDs();
       expect(FakeMatrixApi.api['GET']!['/client/r0/account/3pid']({}),
-          {'threepids': response.map((t) => t.toJson()).toList()});
+          {'threepids': response?.map((t) => t.toJson()).toList()});
       matrixApi.homeserver = matrixApi.accessToken = null;
     });
     test('addThirdPartyIdentifier', () async {
@@ -537,13 +535,13 @@ void main() {
       matrixApi.homeserver = Uri.parse('https://fakeserver.notexisting');
       matrixApi.accessToken = '1234';
 
-      final states = await (matrixApi.getMembersByRoom(
+      final states = await matrixApi.getMembersByRoom(
         '!localpart:server.abc',
         at: '1234',
         membership: Membership.join,
         notMembership: Membership.leave,
-      ) as FutureOr<List<MatrixEvent>>);
-      expect(states.length, 1);
+      );
+      expect(states?.length, 1);
 
       matrixApi.homeserver = matrixApi.accessToken = null;
     });
@@ -551,11 +549,11 @@ void main() {
       matrixApi.homeserver = Uri.parse('https://fakeserver.notexisting');
       matrixApi.accessToken = '1234';
 
-      final states = await (matrixApi.getJoinedMembersByRoom(
+      final states = await matrixApi.getJoinedMembersByRoom(
         '!localpart:server.abc',
-      ) as FutureOr<Map<String, RoomMember>>);
-      expect(states.length, 1);
-      expect(states['@bar:example.com']!.toJson(), {
+      );
+      expect(states?.length, 1);
+      expect(states?['@bar:example.com']?.toJson(), {
         'display_name': 'Bar',
         'avatar_url': 'mxc://riot.ovh/printErCATzZijQsSDWorRaK'
       });
@@ -667,8 +665,8 @@ void main() {
       );
 
       expect(
-          FakeMatrixApi.api['GET']!
-              ['/client/r0/directory/room/%23testalias%3Aexample.com']({}),
+          FakeMatrixApi.api['GET']![
+              '/client/r0/directory/room/%23testalias%3Aexample.com']({}),
           roomAliasInformation.toJson());
 
       matrixApi.homeserver = matrixApi.accessToken = null;
@@ -851,8 +849,8 @@ void main() {
       );
 
       expect(
-          FakeMatrixApi.api['POST']!
-              ['/client/r0/publicRooms?server=example.com']({}),
+          FakeMatrixApi
+              .api['POST']!['/client/r0/publicRooms?server=example.com']({}),
           response.toJson());
 
       matrixApi.homeserver = matrixApi.accessToken = null;
@@ -913,8 +911,8 @@ void main() {
 
       final response = await matrixApi.getUserProfile('@alice:example.com');
       expect(
-          FakeMatrixApi.api['GET']!
-              ['/client/r0/profile/%40alice%3Aexample.com']({}),
+          FakeMatrixApi
+              .api['GET']!['/client/r0/profile/%40alice%3Aexample.com']({}),
           response.toJson());
 
       matrixApi.homeserver = matrixApi.accessToken = null;
@@ -1017,8 +1015,8 @@ void main() {
         ts: 10,
       );
       expect(
-          FakeMatrixApi.api['GET']!
-              ['/media/r0/preview_url?url=https%3A%2F%2Fmatrix.org&ts=10']({}),
+          FakeMatrixApi.api['GET']![
+              '/media/r0/preview_url?url=https%3A%2F%2Fmatrix.org&ts=10']({}),
           openGraphData.toJson());
 
       matrixApi.homeserver = matrixApi.accessToken = null;
@@ -1048,9 +1046,9 @@ void main() {
       matrixApi.homeserver = Uri.parse('https://fakeserver.notexisting');
       matrixApi.accessToken = '1234';
 
-      final devices = await (matrixApi.getDevices() as FutureOr<List<Device>>);
+      final devices = await matrixApi.getDevices();
       expect(FakeMatrixApi.api['GET']!['/client/r0/devices']({})['devices'],
-          devices.map((i) => i.toJson()).toList());
+          devices?.map((i) => i.toJson()).toList());
 
       matrixApi.homeserver = matrixApi.accessToken = null;
     });
@@ -1117,12 +1115,12 @@ void main() {
         token: '1234',
       );
       expect(
-          response
-              .deviceKeys!['@alice:example.com']!['JLAFKJWSCS']!.deviceDisplayName,
+          response.deviceKeys!['@alice:example.com']!['JLAFKJWSCS']!
+              .deviceDisplayName,
           'Alices mobile phone');
       expect(
-          FakeMatrixApi.api['POST']!
-              ['/client/r0/keys/query']({'device_keys': {}}),
+          FakeMatrixApi
+              .api['POST']!['/client/r0/keys/query']({'device_keys': {}}),
           response.toJson());
 
       matrixApi.homeserver = matrixApi.accessToken = null;
@@ -1242,10 +1240,10 @@ void main() {
       matrixApi.homeserver = Uri.parse('https://fakeserver.notexisting');
       matrixApi.accessToken = '1234';
 
-      final response = await (matrixApi.getPushers() as FutureOr<List<Pusher>>);
+      final response = await matrixApi.getPushers();
       expect(
         FakeMatrixApi.api['GET']!['/client/r0/pushers']({}),
-        {'pushers': response.map((i) => i.toJson()).toList()},
+        {'pushers': response?.map((i) => i.toJson()).toList()},
       );
 
       matrixApi.homeserver = matrixApi.accessToken = null;
@@ -1281,8 +1279,8 @@ void main() {
         only: '1234',
       );
       expect(
-        FakeMatrixApi.api['GET']!
-            ['/client/r0/notifications?from=1234&limit=10&only=1234']({}),
+        FakeMatrixApi.api['GET']![
+            '/client/r0/notifications?from=1234&limit=10&only=1234']({}),
         response.toJson(),
       );
 
@@ -1307,8 +1305,8 @@ void main() {
       final response =
           await matrixApi.getPushRule('global', PushRuleKind.content, 'nocake');
       expect(
-        FakeMatrixApi.api['GET']!
-            ['/client/r0/pushrules/global/content/nocake']({}),
+        FakeMatrixApi
+            .api['GET']!['/client/r0/pushrules/global/content/nocake']({}),
         response.toJson(),
       );
 
@@ -1407,8 +1405,8 @@ void main() {
       final response =
           await matrixApi.getEvents(from: '1234', roomId: '!1234', timeout: 10);
       expect(
-        FakeMatrixApi.api['GET']!
-            ['/client/r0/events?from=1234&timeout=10&roomId=%211234']({}),
+        FakeMatrixApi.api['GET']![
+            '/client/r0/events?from=1234&timeout=10&roomId=%211234']({}),
         response.toJson(),
       );
 
@@ -1418,12 +1416,12 @@ void main() {
       matrixApi.homeserver = Uri.parse('https://fakeserver.notexisting');
       matrixApi.accessToken = '1234';
 
-      final response = await (matrixApi.getRoomTags(
-          '@alice:example.com', '!localpart:example.com') as FutureOr<Map<String, Tag>>);
+      final response = await matrixApi.getRoomTags(
+          '@alice:example.com', '!localpart:example.com');
       expect(
         FakeMatrixApi.api['GET']![
             '/client/r0/user/%40alice%3Aexample.com/rooms/!localpart%3Aexample.com/tags']({}),
-        {'tags': response.map((k, v) => MapEntry(k, v.toJson()))},
+        {'tags': response?.map((k, v) => MapEntry(k, v.toJson()))},
       );
 
       matrixApi.homeserver = matrixApi.accessToken = null;
@@ -1507,8 +1505,8 @@ void main() {
 
       final response = await matrixApi.getWhoIs('@alice:example.com');
       expect(
-        FakeMatrixApi.api['GET']!
-            ['/client/r0/admin/whois/%40alice%3Aexample.com']({}),
+        FakeMatrixApi
+            .api['GET']!['/client/r0/admin/whois/%40alice%3Aexample.com']({}),
         response.toJson(),
       );
 
@@ -1521,8 +1519,8 @@ void main() {
       final response = await matrixApi.getEventContext('1234', '1234',
           limit: 10, filter: '{}');
       expect(
-        FakeMatrixApi.api['GET']!
-            ['/client/r0/rooms/1234/context/1234?limit=10&filter=%7B%7D']({}),
+        FakeMatrixApi.api['GET']![
+            '/client/r0/rooms/1234/context/1234?limit=10&filter=%7B%7D']({}),
         response.toJson(),
       );
 
@@ -1596,8 +1594,8 @@ void main() {
       final response =
           await matrixApi.requestThirdPartyLocationsByAlias('1234');
       expect(
-        FakeMatrixApi.api['GET']!
-            ['/client/r0/thirdparty/location?alias=1234']({}),
+        FakeMatrixApi
+            .api['GET']!['/client/r0/thirdparty/location?alias=1234']({}),
         response.map((i) => i.toJson()).toList(),
       );
 
@@ -1621,8 +1619,8 @@ void main() {
 
       final response = await matrixApi.requestOpenIdToken('1234', {});
       expect(
-        FakeMatrixApi.api['POST']!
-            ['/client/r0/user/1234/openid/request_token']({}),
+        FakeMatrixApi
+            .api['POST']!['/client/r0/user/1234/openid/request_token']({}),
         response.toJson(),
       );
 
@@ -1647,8 +1645,8 @@ void main() {
       };
       final ret = await matrixApi.postRoomKeysVersion(algorithm, authData);
       expect(
-          FakeMatrixApi.api['POST']!
-              ['/client/unstable/room_keys/version']({})['version'],
+          FakeMatrixApi.api['POST']!['/client/unstable/room_keys/version'](
+              {})['version'],
           ret);
     });
     test('getRoomKeysVersionCurrent', () async {
@@ -1656,7 +1654,8 @@ void main() {
       matrixApi.accessToken = '1234';
 
       final ret = await matrixApi.getRoomKeysVersionCurrent();
-      expect(FakeMatrixApi.api['GET']!['/client/unstable/room_keys/version']({}),
+      expect(
+          FakeMatrixApi.api['GET']!['/client/unstable/room_keys/version']({}),
           ret.toJson());
     });
     test('putRoomKeysVersion', () async {
@@ -1801,8 +1800,8 @@ void main() {
       });
       final ret = await matrixApi.postRoomKeysKey('5', session);
       expect(
-          FakeMatrixApi.api['PUT']!
-              ['/client/unstable/room_keys/keys?version=5']({}),
+          FakeMatrixApi
+              .api['PUT']!['/client/unstable/room_keys/keys?version=5']({}),
           ret.toJson());
     });
     test('getRoomKeys', () async {
@@ -1811,8 +1810,8 @@ void main() {
 
       final ret = await matrixApi.getRoomKeys('5');
       expect(
-          FakeMatrixApi.api['GET']!
-              ['/client/unstable/room_keys/keys?version=5']({}),
+          FakeMatrixApi
+              .api['GET']!['/client/unstable/room_keys/keys?version=5']({}),
           ret.toJson());
     });
     test('deleteRoomKeys', () async {
@@ -1821,8 +1820,8 @@ void main() {
 
       final ret = await matrixApi.deleteRoomKeys('5');
       expect(
-          FakeMatrixApi.api['DELETE']!
-              ['/client/unstable/room_keys/keys?version=5']({}),
+          FakeMatrixApi
+              .api['DELETE']!['/client/unstable/room_keys/keys?version=5']({}),
           ret.toJson());
     });
     test('AuthenticationData', () {
diff --git a/test/try_get_map_extension_test.dart b/test/try_get_map_extension_test.dart
index 43317512..d38a1e68 100644
--- a/test/try_get_map_extension_test.dart
+++ b/test/try_get_map_extension_test.dart
@@ -1,4 +1,3 @@
-
 /* MIT License
 * 
 * Copyright (C) 2019, 2020, 2021 Famedly GmbH