diff --git a/client/src/app/core/services/collectionStringModelMapper.service.ts b/client/src/app/core/services/collectionStringModelMapper.service.ts
index 8a26d5a43..e9d4ebc18 100644
--- a/client/src/app/core/services/collectionStringModelMapper.service.ts
+++ b/client/src/app/core/services/collectionStringModelMapper.service.ts
@@ -1,4 +1,4 @@
-import { ModelConstructor } from '../../shared/models/base.model';
+import { ModelConstructor, BaseModel } from '../../shared/models/base.model';
 
 /**
  * Registeres the mapping of collection strings <--> actual types. Every Model should register itself here.
@@ -8,14 +8,14 @@ export class CollectionStringModelMapperService {
      * Mapps collection strings to model constructors. Accessed by {@method registerCollectionElement} and
      * {@method getCollectionStringType}.
      */
-    private static collectionStringsTypeMapping: { [collectionString: string]: ModelConstructor } = {};
+    private static collectionStringsTypeMapping: { [collectionString: string]: ModelConstructor<BaseModel> } = {};
 
     /**
      * Registers the type to the collection string
      * @param collectionString
      * @param type
      */
-    public static registerCollectionElement(collectionString: string, type: ModelConstructor) {
+    public static registerCollectionElement(collectionString: string, type: ModelConstructor<BaseModel>) {
         CollectionStringModelMapperService.collectionStringsTypeMapping[collectionString] = type;
     }
 
@@ -23,7 +23,7 @@ export class CollectionStringModelMapperService {
      * Returns the constructor of the requested collection or undefined, if it is not registered.
      * @param collectionString the requested collection
      */
-    public static getModelConstructor(collectionString: string): ModelConstructor {
+    public static getModelConstructor(collectionString: string): ModelConstructor<BaseModel> {
         return CollectionStringModelMapperService.collectionStringsTypeMapping[collectionString];
     }
 
@@ -31,7 +31,7 @@ export class CollectionStringModelMapperService {
      * Returns the collection string of a given ModelConstructor or undefined, if it is not registered.
      * @param ctor
      */
-    public static getCollectionString(ctor: ModelConstructor): string {
+    public static getCollectionString(ctor: ModelConstructor<BaseModel>): string {
         return Object.keys(CollectionStringModelMapperService.collectionStringsTypeMapping).find(
             (collectionString: string) => {
                 return ctor === CollectionStringModelMapperService.collectionStringsTypeMapping[collectionString];
diff --git a/client/src/app/core/services/data-store.service.ts b/client/src/app/core/services/data-store.service.ts
index 92feec958..8d22a4599 100644
--- a/client/src/app/core/services/data-store.service.ts
+++ b/client/src/app/core/services/data-store.service.ts
@@ -182,7 +182,7 @@ export class DataStoreService {
         });
     }
 
-    private getCollectionString(collectionType: ModelConstructor | string): string {
+    private getCollectionString<T extends BaseModel>(collectionType: ModelConstructor<T> | string): string {
         if (typeof collectionType === 'string') {
             return collectionType;
         } else {
@@ -197,10 +197,10 @@ export class DataStoreService {
      * @param ids One ID of the BaseModel
      * @return The given BaseModel-subclass instance
      * @example: this.DS.get(User, 1)
-     * @example: this.DS.get('core/countdown', 2)
+     * @example: this.DS.get<Countdown>('core/countdown', 2)
      */
-    public get<T extends BaseModel>(collectionType: ModelConstructor | string, id: number): T {
-        const collectionString = this.getCollectionString(collectionType);
+    public get<T extends BaseModel>(collectionType: ModelConstructor<T> | string, id: number): T {
+        const collectionString = this.getCollectionString<T>(collectionType);
 
         const collection: ModelCollection = this.modelStore[collectionString];
         if (!collection) {
@@ -211,14 +211,16 @@ export class DataStoreService {
     }
 
     /**
-     * Read multiple ID's from dataStore
+     * Read multiple ID's from dataStore.
+     *
      * @param collectionType The desired BaseModel or collectionString to be read from the dataStore
      * @param ids Multiple IDs as a list of IDs of BaseModel
      * @return The BaseModel-list corresponding to the given ID(s)
-     * @example: this.DS.get(User, [1,2,3,4,5])
+     * @example: this.DS.getMany(User, [1,2,3,4,5])
+     * @example: this.DS.getMany<User>('users/user', [1,2,3,4,5])
      */
-    public getMany<T extends BaseModel>(collectionType: ModelConstructor | string, ids: number[]): T[] {
-        const collectionString = this.getCollectionString(collectionType);
+    public getMany<T extends BaseModel>(collectionType: ModelConstructor<T> | string, ids: number[]): T[] {
+        const collectionString = this.getCollectionString<T>(collectionType);
 
         const collection: ModelCollection = this.modelStore[collectionString];
         if (!collection) {
@@ -234,12 +236,14 @@ export class DataStoreService {
 
     /**
      * Get all models of the given collection from the DataStore.
+     *
      * @param collectionType The desired BaseModel or collectionString to be read from the dataStore
      * @return The BaseModel-list of all instances of T
-     * @example: this.DS.get(User)
+     * @example: this.DS.getAll(User)
+     * @example: this.DS.getAll<User>('users/user')
      */
-    public getAll<T extends BaseModel>(collectionType: ModelConstructor | string): T[] {
-        const collectionString = this.getCollectionString(collectionType);
+    public getAll<T extends BaseModel>(collectionType: ModelConstructor<T> | string): T[] {
+        const collectionString = this.getCollectionString<T>(collectionType);
 
         const collection: ModelCollection = this.modelStore[collectionString];
         if (!collection) {
@@ -258,14 +262,15 @@ export class DataStoreService {
      * @example this.DS.filter<User>(User, myUser => myUser.first_name === "Max")
      */
     public filter<T extends BaseModel>(
-        collectionType: ModelConstructor | string,
+        collectionType: ModelConstructor<T> | string,
         callback: (model: T) => boolean
     ): T[] {
         return this.getAll<T>(collectionType).filter(callback);
     }
 
     /**
-     * Add one or multiple models to dataStore
+     * Add one or multiple models to dataStore.
+     *
      * @param ...models The model(s) that shall be add use spread operator ("...")
      * @example this.DS.add(new User(1))
      * @example this.DS.add((new User(2), new User(3)))
@@ -296,7 +301,8 @@ export class DataStoreService {
     }
 
     /**
-     * removes one or multiple models from dataStore
+     * removes one or multiple models from dataStore.
+     *
      * @param Type   The desired BaseModel type to be read from the dataStore
      * @param ...ids An or multiple IDs or a list of IDs of BaseModels. use spread operator ("...") for arrays
      * @example this.DS.remove(User, myUser.id, 3, 4)
diff --git a/client/src/app/core/services/operator.service.ts b/client/src/app/core/services/operator.service.ts
index fa9754a43..4777a5355 100644
--- a/client/src/app/core/services/operator.service.ts
+++ b/client/src/app/core/services/operator.service.ts
@@ -140,7 +140,7 @@ export class OperatorService extends OpenSlidesComponent {
     private updatePermissions(): void {
         this.permissions = [];
         if (!this.user) {
-            const defaultGroup = this.DS.get('users/group', 1) as Group;
+            const defaultGroup = this.DS.get<Group>('users/group', 1);
             if (defaultGroup && defaultGroup.permissions instanceof Array) {
                 this.permissions = defaultGroup.permissions;
             }
diff --git a/client/src/app/shared/models/base.model.ts b/client/src/app/shared/models/base.model.ts
index 04da7eca8..5e2059292 100644
--- a/client/src/app/shared/models/base.model.ts
+++ b/client/src/app/shared/models/base.model.ts
@@ -2,8 +2,8 @@ import { OpenSlidesComponent } from 'app/openslides.component';
 import { Deserializable } from './deserializable.model';
 import { CollectionStringModelMapperService } from '../../core/services/collectionStringModelMapper.service';
 
-export interface ModelConstructor {
-    new (...args: any[]): BaseModel;
+export interface ModelConstructor<T extends BaseModel> {
+    new (...args: any[]): T;
 }
 
 /**
diff --git a/client/src/app/shared/models/motions/motion-block.ts b/client/src/app/shared/models/motions/motion-block.ts
index 23c425ab3..88d685131 100644
--- a/client/src/app/shared/models/motions/motion-block.ts
+++ b/client/src/app/shared/models/motions/motion-block.ts
@@ -1,4 +1,5 @@
 import { BaseModel } from '../base.model';
+import { Item } from '../agenda/item';
 
 /**
  * Representation of a motion block.
@@ -19,7 +20,7 @@ export class MotionBlock extends BaseModel {
     }
 
     public getAgenda(): BaseModel | BaseModel[] {
-        return this.DS.get('agenda/item', this.agenda_item_id);
+        return this.DS.get<Item>('agenda/item', this.agenda_item_id);
     }
 }
 
diff --git a/client/src/app/shared/models/motions/motion.ts b/client/src/app/shared/models/motions/motion.ts
index b3057b001..5704af5fa 100644
--- a/client/src/app/shared/models/motions/motion.ts
+++ b/client/src/app/shared/models/motions/motion.ts
@@ -76,7 +76,7 @@ export class Motion extends BaseModel {
      */
     public initDataStoreValues() {
         // check the containing Workflows in DataStore
-        const allWorkflows = this.DS.getAll<Workflow>(Workflow);
+        const allWorkflows = this.DS.getAll(Workflow);
         allWorkflows.forEach(localWorkflow => {
             if (localWorkflow.isStateContained(this.state_id)) {
                 this.workflow = localWorkflow as Workflow;
diff --git a/client/src/app/shared/models/users/user.ts b/client/src/app/shared/models/users/user.ts
index 7be60bd06..bdd94d95d 100644
--- a/client/src/app/shared/models/users/user.ts
+++ b/client/src/app/shared/models/users/user.ts
@@ -34,7 +34,7 @@ export class User extends BaseModel {
     }
 
     public get groups(): Group[] {
-        return this.DS.getMany<Group>(Group, this.groups_id);
+        return this.DS.getMany(Group, this.groups_id);
     }
 
     public get full_name(): string {
diff --git a/client/src/app/site/motions/category-list/category-list.component.ts b/client/src/app/site/motions/category-list/category-list.component.ts
index 42ae05538..009524180 100644
--- a/client/src/app/site/motions/category-list/category-list.component.ts
+++ b/client/src/app/site/motions/category-list/category-list.component.ts
@@ -53,7 +53,7 @@ export class CategoryListComponent extends BaseComponent implements OnInit {
      */
     public ngOnInit() {
         super.setTitle('Category');
-        this.categoryArray = this.DS.getAll<Category>(Category);
+        this.categoryArray = this.DS.getAll(Category);
         this.dataSource = new MatTableDataSource(this.categoryArray);
         this.dataSource.sort = this.sort;
 
@@ -61,7 +61,7 @@ export class CategoryListComponent extends BaseComponent implements OnInit {
         // The alternative approach is to put the observable as DataSource to the table
         this.DS.changeObservable.subscribe(newModel => {
             if (newModel instanceof Category) {
-                this.categoryArray = this.DS.getAll<Category>(Category);
+                this.categoryArray = this.DS.getAll(Category);
                 this.dataSource.data = this.categoryArray;
             }
         });
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 81faa3488..d23fa6c17 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
@@ -88,7 +88,7 @@ export class MotionDetailComponent extends BaseComponent implements OnInit {
             // load existing motion
             this.route.params.subscribe(params => {
                 // has the motion of the DataStore was initialized before.
-                this.motion = this.DS.get(Motion, params.id) as Motion;
+                this.motion = this.DS.get(Motion, params.id);
 
                 // Observe motion to get the motion in the parameter and also get the changes
                 this.DS.changeObservable.subscribe(newModel => {
@@ -165,7 +165,7 @@ export class MotionDetailComponent extends BaseComponent implements OnInit {
      * return all Categories.
      */
     public getMotionCategories(): Category[] {
-        return this.DS.getAll<Category>(Category);
+        return this.DS.getAll(Category);
     }
 
     /**
diff --git a/client/src/app/site/motions/motion-list/motion-list.component.ts b/client/src/app/site/motions/motion-list/motion-list.component.ts
index 290771bd1..e2c6b3f7d 100644
--- a/client/src/app/site/motions/motion-list/motion-list.component.ts
+++ b/client/src/app/site/motions/motion-list/motion-list.component.ts
@@ -93,8 +93,8 @@ export class MotionListComponent extends BaseComponent implements OnInit {
      */
     public ngOnInit() {
         super.setTitle('Motions');
-        this.workflowArray = this.DS.getAll<Workflow>(Workflow);
-        this.motionArray = this.DS.getAll<Motion>(Motion);
+        this.workflowArray = this.DS.getAll(Workflow);
+        this.motionArray = this.DS.getAll(Motion);
         this.dataSource = new MatTableDataSource(this.motionArray);
         this.dataSource.paginator = this.paginator;
         this.dataSource.sort = this.sort;
@@ -103,7 +103,7 @@ export class MotionListComponent extends BaseComponent implements OnInit {
         // The alternative approach is to put the observable as DataSource to the table
         this.DS.changeObservable.subscribe(newModel => {
             if (newModel instanceof Motion) {
-                this.motionArray = this.DS.getAll<Motion>(Motion);
+                this.motionArray = this.DS.getAll(Motion);
                 this.dataSource.data = this.motionArray;
             }
         });