Flutter: inherit from abstract stateless widget

I have a class that has to take a custom widget. This one can have two different implementations, so I would like to have an abstract class as interface and create two other classes those extend the abstract one. So, I have:

abstract class ICustomWidget extends StatelessWidget{}

class A extends ICustomWidget{

  @override
  Widget build(BuildContext context) =>
     //Implementation
}

class B extends ICustomWidget {
  @override
  Widget build(BuildContext context) =>
     //Implementation
}

I want to ask if this is the right way to do this or there is another one. Thanks

Rather than extends, I would use implements, because ICustomWidget is an interface, not a class, except if you can give more context and/or code sample.

Here's the sample code for interface

abstract class ICustomWidget {
// or
// abstract class ICustomWidget extends StatelessWidget {
  void myProtocal();
}

class A extends StatelessWidget implements ICustomWidget {

  @override
  void myProtocal() {
    // TODO: implement myProtocal
  }

  @override
  Widget build(BuildContext context) {
     //Implementation
  }
}

class B extends ICustomWidget {
  // compilation error, `myProtocal` not implemented
  @override
  Widget build(BuildContext context) {
     //Implementation
  }
}