code: def app(self):
          
          app = self._app or current_app
  
          if not in_app_context(app):
              raise RuntimeError("This component hasn't been initialized yet "
                                 "and an app context doesn't exist.")
  
          # If current_app is the app, this must be used in order for their IDs
          # to be the same, as current_app will wrap the app in a proxy.
          if hasattr(app, '_get_current_object'):
              app = app._get_current_object()
  
          return app
docs: Internal method that will supply the app to use internally.
  
          Returns:
              flask.Flask: The app to use within the component.
  
          Raises:
              RuntimeError: This is raised if no app was provided to the
                  component and the method is being called outside of an
                  application context.