code: def register(self, app, route, endpoint=None):
          # type: (Flask, str, str) -> None
          
          if app is None or not isinstance(app, Flask):
              raise TypeError("Expected a valid Flask instance")
  
          if route is None or not isinstance(route, str):
              raise TypeError("Expected a valid URL rule string")
  
          app.add_url_rule(
              route, view_func=self.dispatch_request, methods=["POST"],
              endpoint=endpoint)
docs: Method to register the routing on the app at provided route.
  
          This is a utility method, that can be used for registering the
          ``dispatch_request`` on the provided :py:class:`flask.Flask`
          application at the provided URL ``route``.
  
          :param app: A :py:class:`flask.Flask` application instance
          :type app: flask.Flask
          :param route: The URL rule where the skill dispatch has to be
              registered
          :type route: str
          :param endpoint: The endpoint for the registered URL rule.
              This can be used to set multiple skill endpoints on same app.
          :type endpoint: str
          :rtype: None
          :raises: :py:class:`TypeError` if ``app`` or `route`` is not
              provided or is of an invalid type