I am wondering if I have to implement the `ControlValueAccessor` to get the same behavior as with the `DefaultValueAccessor` for my own component or can I extend the class?

Extending the class ends with a template parse error (yes, the component is already part of the module).

module:

```
@NgModule({
    imports: [
        BrowserModule,
        HttpModule,
        FormsModule,
    ],
    declarations: [
        AppComponent ,
        DatePickerComponent,
    ],
    bootstrap:    [ AppComponent ],
})
export class AppModule { }

```

component:

```
export class DatePickerComponent extends DefaultValueAccessor {

```

error:

```
Unhandled Promise rejection: Template parse errors:
'date-picker' is not a known element:
1. If 'date-picker' is an Angular component, then verify that it is part of this module.
2. If 'date-picker' is a Web Component then add "CUSTOM_ELEMENTS_SCHEMA" to the '@NgModule.schemas' of this component to suppress this message. ("
    <div class="col-sm-7">
        <div class="input-group">
            [ERROR ->]<date-picker [name]="beginn" [(ngModel)]="startDate"></date-picker>
        </div>
        <p id="b"): 

```