diff --git a/.gitignore b/.gitignore
index ddfd4ee0b..bcc3cb318 100644
--- a/.gitignore
+++ b/.gitignore
@@ -63,6 +63,7 @@ client/node_modules
 
 # misc
 Compodoc
+Compodocmodules
 client/.sass-cache
 client/connect.lock
 client/coverage
diff --git a/client/src/app/core/services/auth.service.ts b/client/src/app/core/services/auth.service.ts
index 50fc5e159..77fd75c70 100644
--- a/client/src/app/core/services/auth.service.ts
+++ b/client/src/app/core/services/auth.service.ts
@@ -56,7 +56,7 @@ export class AuthService extends OpenSlidesComponent {
         };
         return this.http.post<LoginResponse>(environment.urlPrefix + '/users/login/', user).pipe(
             tap((response: LoginResponse) => {
-                this.operator.user = new User().deserialize(response.user);
+                this.operator.user = new User(response.user);
             }),
             catchError(this.handleError())
         ) as Observable<LoginResponse>;
diff --git a/client/src/app/core/services/autoupdate.service.ts b/client/src/app/core/services/autoupdate.service.ts
index 2496d9bfb..4b5e95e0e 100644
--- a/client/src/app/core/services/autoupdate.service.ts
+++ b/client/src/app/core/services/autoupdate.service.ts
@@ -66,7 +66,7 @@ export class AutoupdateService extends OpenSlidesComponent {
                 /*throw new Error*/ console.log(`Unregistered resource ${collection}`);
                 return;
             }
-            this.DS.add(...autoupdate.changed[collection].map(_obj => new targetClass().deserialize(_obj.data)));
+            this.DS.add(...autoupdate.changed[collection].map(_obj => new targetClass(_obj.data)));
         });
     }
 
diff --git a/client/src/app/core/services/data-store.service.ts b/client/src/app/core/services/data-store.service.ts
index 764447dad..f9fdf261f 100644
--- a/client/src/app/core/services/data-store.service.ts
+++ b/client/src/app/core/services/data-store.service.ts
@@ -129,7 +129,7 @@ export class DataStoreService {
             if (target) {
                 Object.keys(serializedStore[collectionString]).forEach(id => {
                     const data = JSON.parse(serializedStore[collectionString][id]);
-                    storage[collectionString][id] = new target().deserialize(data);
+                    storage[collectionString][id] = new target(data);
                 });
             }
         });
diff --git a/client/src/app/core/services/operator.service.ts b/client/src/app/core/services/operator.service.ts
index 0667d7363..0983ff233 100644
--- a/client/src/app/core/services/operator.service.ts
+++ b/client/src/app/core/services/operator.service.ts
@@ -107,7 +107,7 @@ export class OperatorService extends OpenSlidesComponent {
         return this.http.get<WhoAmIResponse>(environment.urlPrefix + '/users/whoami/').pipe(
             tap((response: WhoAmIResponse) => {
                 if (response && response.user_id) {
-                    this.user = new User().deserialize(response.user);
+                    this.user = new User(response.user);
                 }
             }),
             catchError(this.handleError())
diff --git a/client/src/app/shared/models/agenda/item.ts b/client/src/app/shared/models/agenda/item.ts
index 055767de7..b93ab3b6b 100644
--- a/client/src/app/shared/models/agenda/item.ts
+++ b/client/src/app/shared/models/agenda/item.ts
@@ -28,38 +28,12 @@ export class Item extends BaseModel {
     public weight: number;
     public parent_id: number;
 
-    public constructor(
-        id?: number,
-        item_number?: string,
-        title?: string,
-        list_view_title?: string,
-        comment?: string,
-        closed?: boolean,
-        type?: number,
-        is_hidden?: boolean,
-        duration?: number,
-        speakers?: Speaker[],
-        speaker_list_closed?: boolean,
-        content_object?: ContentObject,
-        weight?: number,
-        parent_id?: number
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'agenda/item';
-        this.id = id;
-        this.item_number = item_number;
-        this.title = title;
-        this.list_view_title = list_view_title;
-        this.comment = comment;
-        this.closed = closed;
-        this.type = type;
-        this.is_hidden = is_hidden;
-        this.duration = duration;
-        this.speakers = speakers;
-        this.speaker_list_closed = speaker_list_closed;
-        this.content_object = content_object;
-        this.weight = weight;
-        this.parent_id = parent_id;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     public getSpeakers(): User[] {
@@ -75,15 +49,14 @@ export class Item extends BaseModel {
         return this.DS.get<BaseModel>(this.content_object.collection, this.content_object.id);
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
 
         if (input.speakers instanceof Array) {
             this.speakers = input.speakers.map(speakerData => {
-                return new Speaker().deserialize(speakerData);
+                return new Speaker(speakerData);
             });
         }
-        return this;
     }
 }
 
diff --git a/client/src/app/shared/models/agenda/speaker.ts b/client/src/app/shared/models/agenda/speaker.ts
index e167f7dd3..e37d0e093 100644
--- a/client/src/app/shared/models/agenda/speaker.ts
+++ b/client/src/app/shared/models/agenda/speaker.ts
@@ -17,34 +17,15 @@ export class Speaker implements Deserializable {
 
     /**
      * Needs to be completely optional because agenda has (yet) the optional parameter 'speaker'
-     * @param id
-     * @param user_id
-     * @param begin_time
-     * @param end_time
-     * @param weight
-     * @param marked
-     * @param item_id
+     * @param input
      */
-    public constructor(
-        id?: number,
-        user_id?: number,
-        begin_time?: string,
-        end_time?: string,
-        weight?: number,
-        marked?: boolean,
-        item_id?: number
-    ) {
-        this.id = id;
-        this.user_id = user_id;
-        this.begin_time = begin_time;
-        this.end_time = end_time;
-        this.weight = weight;
-        this.marked = marked;
-        this.item_id = item_id;
+    public constructor(input?: any) {
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/assignments/assignment-user.ts b/client/src/app/shared/models/assignments/assignment-user.ts
index b783c1df5..2ad7a82e5 100644
--- a/client/src/app/shared/models/assignments/assignment-user.ts
+++ b/client/src/app/shared/models/assignments/assignment-user.ts
@@ -13,22 +13,15 @@ export class AssignmentUser implements Deserializable {
 
     /**
      * Needs to be completely optional because assignment has (yet) the optional parameter 'assignment_related_users'
-     * @param id
-     * @param user_id
-     * @param elected
-     * @param assignment_id
-     * @param weight
+     * @param input
      */
-    public constructor(id?: number, user_id?: number, elected?: boolean, assignment_id?: number, weight?: number) {
-        this.id = id;
-        this.user_id = user_id;
-        this.elected = elected;
-        this.assignment_id = assignment_id;
-        this.weight = weight;
+    public constructor(input?: any) {
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/assignments/assignment.ts b/client/src/app/shared/models/assignments/assignment.ts
index 1ae32d750..d90616936 100644
--- a/client/src/app/shared/models/assignments/assignment.ts
+++ b/client/src/app/shared/models/assignments/assignment.ts
@@ -21,30 +21,15 @@ export class Assignment extends BaseModel {
     public agenda_item_id: number;
     public tags_id: number[];
 
-    public constructor(
-        id?: number,
-        title?: string,
-        description?: string,
-        open_posts?: number,
-        phase?: number,
-        assignment_related_users?: AssignmentUser[],
-        poll_description_default?: number,
-        polls?: Poll[],
-        agenda_item_id?: number,
-        tags_id?: number[]
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'assignments/assignment';
-        this.id = id;
-        this.title = title;
-        this.description = description;
-        this.open_posts = open_posts;
-        this.phase = phase;
-        this.assignment_related_users = assignment_related_users || []; // TODO Array
-        this.poll_description_default = poll_description_default;
-        this.polls = polls || Array(); // TODO Array
-        this.agenda_item_id = agenda_item_id;
-        this.tags_id = tags_id;
+        this.assignment_related_users = []; // TODO Array
+        this.polls = Array(); // TODO Array
+
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     public getAssignmentReleatedUsers(): BaseModel | BaseModel[] {
@@ -59,23 +44,22 @@ export class Assignment extends BaseModel {
         return this.DS.getMany<Tag>('core/tag', this.tags_id);
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
 
         if (input.assignment_related_users instanceof Array) {
             this.assignment_related_users = [];
             input.assignment_related_users.forEach(assignmentUserData => {
-                this.assignment_related_users.push(new AssignmentUser().deserialize(assignmentUserData));
+                this.assignment_related_users.push(new AssignmentUser(assignmentUserData));
             });
         }
 
         if (input.polls instanceof Array) {
             this.polls = [];
             input.polls.forEach(pollData => {
-                this.polls.push(new Poll().deserialize(pollData));
+                this.polls.push(new Poll(pollData));
             });
         }
-        return this;
     }
 }
 
diff --git a/client/src/app/shared/models/assignments/poll-option.ts b/client/src/app/shared/models/assignments/poll-option.ts
index 32ec3f08d..308b0088a 100644
--- a/client/src/app/shared/models/assignments/poll-option.ts
+++ b/client/src/app/shared/models/assignments/poll-option.ts
@@ -16,31 +16,15 @@ export class PollOption implements Deserializable {
 
     /**
      * Needs to be completely optional because poll has (yet) the optional parameter 'poll-options'
-     * @param id
-     * @param candidate_id
-     * @param is_elected
-     * @param votes
-     * @param poll_id
-     * @param weight
+     * @param input
      */
-    public constructor(
-        id?: number,
-        candidate_id?: number,
-        is_elected?: boolean,
-        votes?: number[],
-        poll_id?: number,
-        weight?: number
-    ) {
-        this.id = id;
-        this.candidate_id = candidate_id;
-        this.is_elected = is_elected;
-        this.votes = votes;
-        this.poll_id = poll_id;
-        this.weight = weight;
+    public constructor(input?: any) {
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/assignments/poll.ts b/client/src/app/shared/models/assignments/poll.ts
index d4dca9b83..8f402a99a 100644
--- a/client/src/app/shared/models/assignments/poll.ts
+++ b/client/src/app/shared/models/assignments/poll.ts
@@ -19,50 +19,23 @@ export class Poll implements Deserializable {
 
     /**
      * Needs to be completely optional because assignment has (yet) the optional parameter 'polls'
-     * @param id
-     * @param pollmethod
-     * @param description
-     * @param published
-     * @param options
-     * @param votesvalid
-     * @param votesinvalid
-     * @param votescast
-     * @param has_votes
-     * @param assignment_id
+     * @param input
      */
-    public constructor(
-        id?: number,
-        pollmethod?: string,
-        description?: string,
-        published?: boolean,
-        options?: PollOption[],
-        votesvalid?: number,
-        votesinvalid?: number,
-        votescast?: number,
-        has_votes?: boolean,
-        assignment_id?: number
-    ) {
-        this.id = id;
-        this.pollmethod = pollmethod;
-        this.description = description;
-        this.published = published;
-        this.options = options || Array(new PollOption()); // TODO Array
-        this.votesvalid = votesvalid;
-        this.votesinvalid = votesinvalid;
-        this.votescast = votescast;
-        this.has_votes = has_votes;
-        this.assignment_id = assignment_id;
+    public constructor(input?: any) {
+        this.options = [new PollOption()];
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
 
         if (input.options instanceof Array) {
             this.options = [];
             input.options.forEach(pollOptionData => {
-                this.options.push(new PollOption().deserialize(pollOptionData));
+                this.options.push(new PollOption(pollOptionData));
             });
         }
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/base.model.ts b/client/src/app/shared/models/base.model.ts
index 4bc0f68db..5de4186d4 100644
--- a/client/src/app/shared/models/base.model.ts
+++ b/client/src/app/shared/models/base.model.ts
@@ -57,8 +57,7 @@ export abstract class BaseModel extends OpenSlidesComponent implements Deseriali
      * Inherited to children, can be overwritten for special use cases
      * @param input JSON data for deserialization.
      */
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/core/chat-message.ts b/client/src/app/shared/models/core/chat-message.ts
index cc2685ca5..60080a8f0 100644
--- a/client/src/app/shared/models/core/chat-message.ts
+++ b/client/src/app/shared/models/core/chat-message.ts
@@ -1,4 +1,5 @@
 import { BaseModel } from '../base.model';
+import { User } from '../users/user';
 
 /**
  * Representation of chat messages.
@@ -11,17 +12,16 @@ export class ChatMessage extends BaseModel {
     public timestamp: string; // TODO: Type for timestamp
     public user_id: number;
 
-    public constructor(id?: number, message?: string, timestamp?: string, user_id?: number) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'core/chat-message';
-        this.id = id;
-        this.message = message;
-        this.timestamp = timestamp;
-        this.user_id = user_id;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public getUser(): BaseModel | BaseModel[] {
-        return this.DS.get('users/user', this.user_id);
+    public getUser(): User {
+        return this.DS.get<User>('users/user', this.user_id);
     }
 }
 
diff --git a/client/src/app/shared/models/core/config.ts b/client/src/app/shared/models/core/config.ts
index 88c659f77..c85275442 100644
--- a/client/src/app/shared/models/core/config.ts
+++ b/client/src/app/shared/models/core/config.ts
@@ -10,12 +10,12 @@ export class Config extends BaseModel {
     public key: string;
     public value: Object;
 
-    public constructor(id?: number, key?: string, value?: Object) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'core/config';
-        this.id = id;
-        this.key = key;
-        this.value = value;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 }
 
diff --git a/client/src/app/shared/models/core/countdown.ts b/client/src/app/shared/models/core/countdown.ts
index 5a287a94d..d2fe0320a 100644
--- a/client/src/app/shared/models/core/countdown.ts
+++ b/client/src/app/shared/models/core/countdown.ts
@@ -12,20 +12,12 @@ export class Countdown extends BaseModel {
     public countdown_time: number;
     public running: boolean;
 
-    public constructor(
-        id?: number,
-        countdown_time?: number,
-        default_time?: number,
-        description?: string,
-        running?: boolean
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'core/countdown';
-        this.id = id;
-        this.description = description;
-        this.default_time = default_time;
-        this.countdown_time = countdown_time;
-        this.running = running;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 }
 
diff --git a/client/src/app/shared/models/core/projector-message.ts b/client/src/app/shared/models/core/projector-message.ts
index d1c377dab..782fbbd56 100644
--- a/client/src/app/shared/models/core/projector-message.ts
+++ b/client/src/app/shared/models/core/projector-message.ts
@@ -9,11 +9,12 @@ export class ProjectorMessage extends BaseModel {
     public id: number;
     public message: string;
 
-    public constructor(id?: number, message?: string) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'core/projector-message';
-        this.id = id;
-        this.message = message;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 }
 
diff --git a/client/src/app/shared/models/core/projector.ts b/client/src/app/shared/models/core/projector.ts
index 0145074bb..271a708c6 100644
--- a/client/src/app/shared/models/core/projector.ts
+++ b/client/src/app/shared/models/core/projector.ts
@@ -16,28 +16,12 @@ export class Projector extends BaseModel {
     public height: number;
     public projectiondefaults: Object[];
 
-    public constructor(
-        id?: number,
-        elements?: Object,
-        scale?: number,
-        scroll?: number,
-        name?: string,
-        blank?: boolean,
-        width?: number,
-        height?: number,
-        projectiondefaults?: Object[]
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'core/projector';
-        this.id = id;
-        this.elements = elements;
-        this.scale = scale;
-        this.scroll = scroll;
-        this.name = name;
-        this.blank = blank;
-        this.width = width;
-        this.height = height;
-        this.projectiondefaults = projectiondefaults;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 }
 
diff --git a/client/src/app/shared/models/core/tag.ts b/client/src/app/shared/models/core/tag.ts
index 82d344d07..e8678bb15 100644
--- a/client/src/app/shared/models/core/tag.ts
+++ b/client/src/app/shared/models/core/tag.ts
@@ -9,11 +9,12 @@ export class Tag extends BaseModel {
     public id: number;
     public name: string;
 
-    public constructor(id?: number, name?: string) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'core/tag';
-        this.id = id;
-        this.name = name;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 }
 
diff --git a/client/src/app/shared/models/deserializable.model.ts b/client/src/app/shared/models/deserializable.model.ts
index 0ed73c2bc..7d2cfd844 100644
--- a/client/src/app/shared/models/deserializable.model.ts
+++ b/client/src/app/shared/models/deserializable.model.ts
@@ -2,12 +2,16 @@
  * Interface tells models to offer a 'deserialize' function
  *
  * Also nested objects and arrays have have to be handled.
- * @example const myUser = new User().deserialize(jsonData)
+ * @example
+ * ``` ts
+ * const myUser = new User();
+ * myUser.deserialize(jsonData);
+ * ```
  */
 export interface Deserializable {
     /**
      * should be used to assign JSON values to the object itself.
      * @param input
      */
-    deserialize(input: any): this;
+    deserialize(input: any): void;
 }
diff --git a/client/src/app/shared/models/mediafiles/file.ts b/client/src/app/shared/models/mediafiles/file.ts
index e41373c95..02009935b 100644
--- a/client/src/app/shared/models/mediafiles/file.ts
+++ b/client/src/app/shared/models/mediafiles/file.ts
@@ -13,13 +13,13 @@ export class File implements Deserializable {
      * @param name The name of the file
      * @param type The tape (jpg, png, pdf)
      */
-    public constructor(name?: string, type?: string) {
-        this.name = name;
-        this.type = type;
+    public constructor(input?: any) {
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/mediafiles/mediafile.ts b/client/src/app/shared/models/mediafiles/mediafile.ts
index 5c7247491..c7a163676 100644
--- a/client/src/app/shared/models/mediafiles/mediafile.ts
+++ b/client/src/app/shared/models/mediafiles/mediafile.ts
@@ -1,5 +1,6 @@
 import { BaseModel } from '../base.model';
 import { File } from './file';
+import { User } from '../users/user';
 
 /**
  * Representation of MediaFile. Has the nested property "File"
@@ -16,36 +17,21 @@ export class Mediafile extends BaseModel {
     public hidden: boolean;
     public timestamp: string;
 
-    public constructor(
-        id?: number,
-        title?: string,
-        mediafile?: File,
-        media_url_prefix?: string,
-        uploader_id?: number,
-        filesize?: string,
-        hidden?: boolean,
-        timestamp?: string
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'mediafiles/mediafile';
-        this.id = id;
-        this.title = title;
-        this.mediafile = mediafile;
-        this.media_url_prefix = media_url_prefix;
-        this.uploader_id = uploader_id;
-        this.filesize = filesize;
-        this.hidden = hidden;
-        this.timestamp = timestamp;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        this.mediafile = new File().deserialize(input.mediafile);
-        return this;
+        this.mediafile = new File(input.mediafile);
     }
 
-    public getUploader(): BaseModel | BaseModel[] {
-        return this.DS.get('users/user', this.uploader_id);
+    public getUploader(): User {
+        return this.DS.get<User>('users/user', this.uploader_id);
     }
 }
 
diff --git a/client/src/app/shared/models/motions/category.ts b/client/src/app/shared/models/motions/category.ts
index 45a9083d0..aae765e05 100644
--- a/client/src/app/shared/models/motions/category.ts
+++ b/client/src/app/shared/models/motions/category.ts
@@ -10,12 +10,12 @@ export class Category extends BaseModel {
     public name: string;
     public prefix: string;
 
-    public constructor(id?: number, name?: string, prefix?: string) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'motions/category';
-        this.id = id;
-        this.name = name;
-        this.prefix = prefix;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     public toString = (): string => {
diff --git a/client/src/app/shared/models/motions/motion-block.ts b/client/src/app/shared/models/motions/motion-block.ts
index bc28442ac..23c425ab3 100644
--- a/client/src/app/shared/models/motions/motion-block.ts
+++ b/client/src/app/shared/models/motions/motion-block.ts
@@ -10,12 +10,12 @@ export class MotionBlock extends BaseModel {
     public title: string;
     public agenda_item_id: number;
 
-    public constructor(id?: number, title?: string, agenda_item_id?: number) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'motions/motion-block';
-        this.id = id;
-        this.title = title;
-        this.agenda_item_id = agenda_item_id;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     public getAgenda(): BaseModel | BaseModel[] {
diff --git a/client/src/app/shared/models/motions/motion-change-reco.ts b/client/src/app/shared/models/motions/motion-change-reco.ts
index a11a42b3f..fb8f9eb4c 100644
--- a/client/src/app/shared/models/motions/motion-change-reco.ts
+++ b/client/src/app/shared/models/motions/motion-change-reco.ts
@@ -16,28 +16,12 @@ export class MotionChangeReco extends BaseModel {
     public text: string;
     public creation_time: string;
 
-    public constructor(
-        id?: number,
-        motion_version_id?: number,
-        rejected?: boolean,
-        type?: number,
-        other_description?: string,
-        line_from?: number,
-        line_to?: number,
-        text?: string,
-        creation_time?: string
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'motions/motion-change-recommendation';
-        this.id = id;
-        this.motion_version_id = motion_version_id;
-        this.rejected = rejected;
-        this.type = type;
-        this.other_description = other_description;
-        this.line_from = line_from;
-        this.line_to = line_to;
-        this.text = text;
-        this.creation_time = creation_time;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 }
 
diff --git a/client/src/app/shared/models/motions/motion-log.ts b/client/src/app/shared/models/motions/motion-log.ts
index f2ec96ef2..2e240ecbc 100644
--- a/client/src/app/shared/models/motions/motion-log.ts
+++ b/client/src/app/shared/models/motions/motion-log.ts
@@ -11,15 +11,13 @@ export class MotionLog implements Deserializable {
     public time: string;
     public message: string;
 
-    public constructor(message_list?: string[], person_id?: number, time?: string, message?: string) {
-        this.message_list = message_list;
-        this.person_id = person_id;
-        this.time = time;
-        this.message = message;
+    public constructor(input?: any) {
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/motions/motion-submitter.ts b/client/src/app/shared/models/motions/motion-submitter.ts
index 334528740..b1399e639 100644
--- a/client/src/app/shared/models/motions/motion-submitter.ts
+++ b/client/src/app/shared/models/motions/motion-submitter.ts
@@ -11,15 +11,13 @@ export class MotionSubmitter implements Deserializable {
     public motion_id: number;
     public weight: number;
 
-    public constructor(id?: number, user_id?: number, motion_id?: number, weight?: number) {
-        this.id = id;
-        this.user_id = user_id;
-        this.motion_id = motion_id;
-        this.weight = weight;
+    public constructor(input?: any) {
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/motions/motion-version.ts b/client/src/app/shared/models/motions/motion-version.ts
index 0fe3a5b68..6fc9ff580 100644
--- a/client/src/app/shared/models/motions/motion-version.ts
+++ b/client/src/app/shared/models/motions/motion-version.ts
@@ -14,26 +14,17 @@ export class MotionVersion implements Deserializable {
     public amendment_paragraphs: string;
     public reason: string;
 
-    public constructor(
-        id?: number,
-        version_number?: number,
-        creation_time?: string,
-        title?: string,
-        text?: string,
-        amendment_paragraphs?: string,
-        reason?: string
-    ) {
-        this.id = id;
-        this.version_number = version_number;
-        this.creation_time = creation_time;
-        this.title = title || '';
-        this.text = text || '';
-        this.amendment_paragraphs = amendment_paragraphs || '';
-        this.reason = reason || '';
+    public constructor(input?: any) {
+        this.title = '';
+        this.text = '';
+        this.reason = '';
+
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 }
diff --git a/client/src/app/shared/models/motions/motion.ts b/client/src/app/shared/models/motions/motion.ts
index 13939a2d5..4f6ab77bf 100644
--- a/client/src/app/shared/models/motions/motion.ts
+++ b/client/src/app/shared/models/motions/motion.ts
@@ -44,49 +44,20 @@ export class Motion extends BaseModel {
     public title: string;
     public text: string;
 
-    public constructor(
-        id?: number,
-        identifier?: string,
-        versions?: MotionVersion[],
-        active_version?: number,
-        parent_id?: number,
-        category_id?: number,
-        motion_block_id?: number,
-        origin?: string,
-        submitters?: MotionSubmitter[],
-        supporters_id?: number[],
-        comments?: Object,
-        state_id?: number,
-        state_required_permission_to_see?: string,
-        recommendation_id?: number,
-        tags_id?: number[],
-        attachments_id?: number[],
-        polls?: BaseModel[],
-        agenda_item_id?: number,
-        log_messages?: MotionLog[]
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'motions/motion';
-        this.id = id;
-        this.identifier = identifier || '';
-        this.versions = versions || [new MotionVersion()];
-        this.active_version = active_version;
-        this.parent_id = parent_id;
-        this.category_id = category_id;
-        this.motion_block_id = motion_block_id;
-        this.origin = origin || '';
-        this.submitters = submitters || [];
-        this.supporters_id = supporters_id;
-        this.comments = comments;
-        this.state_id = state_id;
-        this.state_required_permission_to_see = state_required_permission_to_see || '';
-        this.recommendation_id = recommendation_id;
-        this.tags_id = tags_id;
-        this.attachments_id = attachments_id;
-        this.polls = polls;
-        this.agenda_item_id = agenda_item_id;
-        this.log_messages = log_messages || [];
+        this.identifier = '';
+        this.versions = [new MotionVersion()];
+        this.origin = '';
+        this.submitters = [];
+        this.supporters_id = [];
+        this.state_required_permission_to_see = '';
+        this.log_messages = [];
 
+        if (input) {
+            this.deserialize(input);
+        }
         this.initDataStoreValues();
     }
 
@@ -124,7 +95,8 @@ export class Motion extends BaseModel {
      * @param user the user
      */
     public addSubmitter(user: User) {
-        const newSubmitter = new MotionSubmitter(null, user.id);
+        const newSubmitter = new MotionSubmitter();
+        newSubmitter.user_id = user.id;
         this.submitters.push(newSubmitter);
         console.log('did addSubmitter. this.submitters: ', this.submitters);
     }
@@ -264,31 +236,29 @@ export class Motion extends BaseModel {
         }
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
 
         if (input.versions instanceof Array) {
             this.versions = [];
             input.versions.forEach(motionVersionData => {
-                this.versions.push(new MotionVersion().deserialize(motionVersionData));
+                this.versions.push(new MotionVersion(motionVersionData));
             });
         }
 
         if (input.submitters instanceof Array) {
             this.submitters = [];
             input.submitters.forEach(SubmitterData => {
-                this.submitters.push(new MotionSubmitter().deserialize(SubmitterData));
+                this.submitters.push(new MotionSubmitter(SubmitterData));
             });
         }
 
         if (input.log_messages instanceof Array) {
             this.log_messages = [];
             input.log_messages.forEach(logData => {
-                this.log_messages.push(new MotionLog().deserialize(logData));
+                this.log_messages.push(new MotionLog(logData));
             });
         }
-
-        return this;
     }
 }
 
diff --git a/client/src/app/shared/models/motions/workflow-state.ts b/client/src/app/shared/models/motions/workflow-state.ts
index 5f7af0c12..afeb16aca 100644
--- a/client/src/app/shared/models/motions/workflow-state.ts
+++ b/client/src/app/shared/models/motions/workflow-state.ts
@@ -27,57 +27,12 @@ export class WorkflowState implements Deserializable {
 
     /**
      * Needs to be completely optional because Workflow has (yet) the optional parameter 'states'
-     * @param id
-     * @param name
-     * @param action_word
-     * @param recommendation_label
-     * @param css_class
-     * @param required_permission_to_see
-     * @param allow_support
-     * @param allow_create_poll
-     * @param allow_submitter_edit
-     * @param versioning
-     * @param leave_old_version_active
-     * @param dont_set_identifier
-     * @param show_state_extension_field
-     * @param show_recommendation_extension_field
-     * @param next_states_id
-     * @param workflow_id
+     * @param input If given, it will be deserialized
      */
-    public constructor(
-        id?: number,
-        name?: string,
-        action_word?: string,
-        recommendation_label?: string,
-        css_class?: string,
-        required_permission_to_see?: string,
-        allow_support?: boolean,
-        allow_create_poll?: boolean,
-        allow_submitter_edit?: boolean,
-        versioning?: boolean,
-        leave_old_version_active?: boolean,
-        dont_set_identifier?: boolean,
-        show_state_extension_field?: boolean,
-        show_recommendation_extension_field?: boolean,
-        next_states_id?: number[],
-        workflow_id?: number
-    ) {
-        this.id = id;
-        this.name = name;
-        this.action_word = action_word;
-        this.recommendation_label = recommendation_label;
-        this.css_class = css_class;
-        this.required_permission_to_see = required_permission_to_see;
-        this.allow_support = allow_support;
-        this.allow_create_poll = allow_create_poll;
-        this.allow_submitter_edit = allow_submitter_edit;
-        this.versioning = versioning;
-        this.leave_old_version_active = leave_old_version_active;
-        this.dont_set_identifier = dont_set_identifier;
-        this.show_state_extension_field = show_state_extension_field;
-        this.show_recommendation_extension_field = show_recommendation_extension_field;
-        this.next_states_id = next_states_id;
-        this.workflow_id = workflow_id;
+    public constructor(input?: any) {
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     /**
@@ -94,9 +49,8 @@ export class WorkflowState implements Deserializable {
         return nextStates;
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
-        return this;
     }
 
     public toString = (): string => {
diff --git a/client/src/app/shared/models/motions/workflow.ts b/client/src/app/shared/models/motions/workflow.ts
index 30f8093ae..99b2393d8 100644
--- a/client/src/app/shared/models/motions/workflow.ts
+++ b/client/src/app/shared/models/motions/workflow.ts
@@ -12,13 +12,12 @@ export class Workflow extends BaseModel {
     public states: WorkflowState[];
     public first_state: number;
 
-    public constructor(id?: number, name?: string, states?: WorkflowState[], first_state?: number) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'motions/workflow';
-        this.id = id;
-        this.name = name;
-        this.states = states;
-        this.first_state = first_state;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     /**
@@ -50,15 +49,14 @@ export class Workflow extends BaseModel {
         return targetState as WorkflowState;
     }
 
-    public deserialize(input: any): this {
+    public deserialize(input: any): void {
         Object.assign(this, input);
         if (input.states instanceof Array) {
             this.states = [];
             input.states.forEach(workflowStateData => {
-                this.states.push(new WorkflowState().deserialize(workflowStateData));
+                this.states.push(new WorkflowState(workflowStateData));
             });
         }
-        return this;
     }
 }
 
diff --git a/client/src/app/shared/models/topics/topic.ts b/client/src/app/shared/models/topics/topic.ts
index 8c489c890..c0db048ab 100644
--- a/client/src/app/shared/models/topics/topic.ts
+++ b/client/src/app/shared/models/topics/topic.ts
@@ -14,14 +14,12 @@ export class Topic extends BaseModel {
     public attachments_id: number[];
     public agenda_item_id: number;
 
-    public constructor(id?: number, title?: string, text?: string, attachments_id?: number[], agenda_item_id?: number) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'topics/topic';
-        this.id = id;
-        this.title = title;
-        this.text = text;
-        this.attachments_id = attachments_id;
-        this.agenda_item_id = agenda_item_id;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     public getAttachments(): Mediafile[] {
diff --git a/client/src/app/shared/models/users/group.ts b/client/src/app/shared/models/users/group.ts
index ad3218515..26fac8804 100644
--- a/client/src/app/shared/models/users/group.ts
+++ b/client/src/app/shared/models/users/group.ts
@@ -11,12 +11,12 @@ export class Group extends BaseModel {
     public name: string;
     public permissions: string[];
 
-    public constructor(id?: number, name?: string, permissions?: string[]) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'users/group';
-        this.id = id;
-        this.name = name;
-        this.permissions = permissions;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     public get users() {
diff --git a/client/src/app/shared/models/users/personal-note.ts b/client/src/app/shared/models/users/personal-note.ts
index 223dadd77..26a607704 100644
--- a/client/src/app/shared/models/users/personal-note.ts
+++ b/client/src/app/shared/models/users/personal-note.ts
@@ -1,4 +1,5 @@
 import { BaseModel } from '../base.model';
+import { User } from './user';
 
 /**
  * Representation of users personal note.
@@ -10,16 +11,16 @@ export class PersonalNote extends BaseModel {
     public user_id: number;
     public notes: Object;
 
-    public constructor(id?: number, user_id?: number, notes?: Object) {
+    public constructor(input: any) {
         super();
         this._collectionString = 'users/personal-note';
-        this.id = id;
-        this.user_id = user_id;
-        this.notes = notes;
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
-    public getUser(): BaseModel | BaseModel[] {
-        return this.DS.get('users/user', this.user_id);
+    public getUser(): User {
+        return this.DS.get<User>('users/user', this.user_id);
     }
 }
 
diff --git a/client/src/app/shared/models/users/user.ts b/client/src/app/shared/models/users/user.ts
index 89acd70c3..7be60bd06 100644
--- a/client/src/app/shared/models/users/user.ts
+++ b/client/src/app/shared/models/users/user.ts
@@ -24,42 +24,13 @@ export class User extends BaseModel {
     public is_active: boolean;
     public default_password: string;
 
-    public constructor(
-        id?: number,
-        username?: string,
-        title?: string,
-        first_name?: string,
-        last_name?: string,
-        structure_level?: string,
-        number?: string,
-        about_me?: string,
-        groups_id?: number[],
-        is_present?: boolean,
-        is_committee?: boolean,
-        email?: string,
-        last_email_send?: string,
-        comment?: string,
-        is_active?: boolean,
-        default_password?: string
-    ) {
+    public constructor(input?: any) {
         super();
         this._collectionString = 'users/user';
-        this.id = id;
-        this.username = username;
-        this.title = title;
-        this.first_name = first_name;
-        this.last_name = last_name;
-        this.structure_level = structure_level;
-        this.number = number;
-        this.about_me = about_me;
-        this.groups_id = groups_id;
-        this.is_present = is_present;
-        this.is_committee = is_committee;
-        this.email = email;
-        this.last_email_send = last_email_send;
-        this.comment = comment;
-        this.is_active = is_active;
-        this.default_password = default_password;
+
+        if (input) {
+            this.deserialize(input);
+        }
     }
 
     public get groups(): Group[] {
diff --git a/client/src/app/site/motions/motion-detail/motion-detail.component.ts b/client/src/app/site/motions/motion-detail/motion-detail.component.ts
index 4abc80dd8..7b3ca61cf 100644
--- a/client/src/app/site/motions/motion-detail/motion-detail.component.ts
+++ b/client/src/app/site/motions/motion-detail/motion-detail.component.ts
@@ -106,13 +106,10 @@ export class MotionDetailComponent extends BaseComponent implements OnInit {
      * Async load the values of the motion in the Form.
      */
     public patchForm(formMotion: Motion) {
-        console.log('Motion: ', this.motion);
-        console.log('category_id: ', formMotion);
-
         this.metaInfoForm.patchValue({
-            category_id: formMotion.category.id,
-            state_id: formMotion.state.id,
-            recommendation_id: formMotion.recommendation.id,
+            category_id: formMotion.category_id,
+            state_id: formMotion.state_id,
+            recommendation_id: formMotion.recommendation_id,
             identifier: formMotion.identifier,
             origin: formMotion.origin
         });
diff --git a/client/src/app/site/start/start.component.ts b/client/src/app/site/start/start.component.ts
index 2b677a819..56a354860 100644
--- a/client/src/app/site/start/start.component.ts
+++ b/client/src/app/site/start/start.component.ts
@@ -80,18 +80,18 @@ export class StartComponent extends BaseComponent implements OnInit {
      */
     public DataStoreTest() {
         console.log('add a user to dataStore');
-        this.DS.add(new User(100));
+        this.DS.add(new User({ id: 100 }));
         console.log('add three users to dataStore');
-        this.DS.add(new User(200), new User(201), new User(202));
+        this.DS.add(new User({ id: 200 }), new User({ id: 201 }), new User({ id: 202 }));
         console.log('use the spread operator "..." to add an array');
         const userArray = [];
         for (let i = 300; i < 400; i++) {
-            userArray.push(new User(i));
+            userArray.push(new User({ id: i }));
         }
         this.DS.add(...userArray);
 
         console.log('try to get user with ID 1:');
-        const user1fromStore = this.DS.get(User, 1);
+        const user1fromStore = this.DS.get<User>(User, 1);
         console.log('the user: ', user1fromStore);
 
         console.log('remove a single user:');
@@ -102,7 +102,7 @@ export class StartComponent extends BaseComponent implements OnInit {
         this.DS.remove(User, ...[321, 363, 399]);
 
         console.log('test filter: ');
-        console.log(this.DS.filter(User, user => user.id === 1));
+        console.log(this.DS.filter<User>(User, user => user.id === 1));
     }
 
     /**
@@ -153,32 +153,30 @@ export class StartComponent extends BaseComponent implements OnInit {
 
         for (let i = 1; i <= requiredMotions; ++i) {
             // version
-            const newMotionVersion = new MotionVersion(
-                200 + i,
-                1,
-                'now',
-                'GenMo ' + i,
-                longMotionText,
-                null,
-                longMotionText
-            );
+            const newMotionVersion = new MotionVersion({
+                id: 200 + i,
+                version_number: 1,
+                create_time: 'now',
+                title: 'GenMo ' + i,
+                text: longMotionText,
+                reason: longMotionText
+            });
             // submitter
-            const newMotionSubmitter = new MotionSubmitter(1, 1, 200 + 1, 0);
+            const newMotionSubmitter = new MotionSubmitter({
+                id: 1,
+                user_id: 1,
+                motion_id: 200 + i,
+                weight: 0
+            });
             // motion
-            const newMotion = new Motion(
-                200 + i,
-                'GenMo ' + i,
-                [newMotionVersion],
-                null,
-                null,
-                null,
-                null,
-                'Generated',
-                [newMotionSubmitter],
-                null,
-                null,
-                1
-            );
+            const newMotion = new Motion({
+                id: 200 + i,
+                identifier: 'GenMo ' + i,
+                versions: [newMotionVersion],
+                origin: 'Generated',
+                submitters: [newMotionSubmitter],
+                state_id: 1
+            });
             newMotionsArray.push(newMotion);
         }
         this.DS.add(...newMotionsArray);