code: def init_app(self, app):
          # type: (Flask) -> None
          
          app.config.setdefault(VERIFY_SIGNATURE_APP_CONFIG, True)
          app.config.setdefault(VERIFY_TIMESTAMP_APP_CONFIG, True)
  
          if EXTENSION_NAME not in app.extensions:
              app.extensions[EXTENSION_NAME] = {}
  
          app.extensions[EXTENSION_NAME][self._skill_id] = self
  
          with app.app_context():
              self._create_webservice_handler(self._skill, self._verifiers)
docs: Register the extension on the given Flask application.
  
          Use this function only when no Flask application was provided
          in the ``app`` keyword argument to the constructor of this class.
  
          The function sets ``True`` defaults for
          :py:const:`VERIFY_SIGNATURE_APP_CONFIG` and
          :py:const:`VERIFY_TIMESTAMP_APP_CONFIG` configurations. It adds
          the skill id: self instance mapping to the application
          extensions, and creates a
          :py:class:`ask_sdk_webservice_support.webservice_handler.WebserviceHandler`
          instance, for request verification and dispatch.
  
          :param app: A :py:class:`flask.Flask` application instance
          :type app: flask.Flask
          :rtype: None