code: def add_resource(self, resource, *urls, **kwargs):
          
          if self.app is not None:
              self._register_view(self.app, resource, *urls, **kwargs)
          else:
              self.resources.append((resource, urls, kwargs))
docs: Adds a resource to the api.
  
          :param resource: the class name of your resource
          :type resource: :class:`Type[Resource]`
  
          :param urls: one or more url routes to match for the resource, standard
                       flask routing rules apply.  Any url variables will be
                       passed to the resource method as args.
          :type urls: str
  
          :param endpoint: endpoint name (defaults to :meth:`Resource.__name__.lower`
              Can be used to reference this route in :class:`fields.Url` fields
          :type endpoint: str
  
          :param resource_class_args: args to be forwarded to the constructor of
              the resource.
          :type resource_class_args: tuple
  
          :param resource_class_kwargs: kwargs to be forwarded to the constructor
              of the resource.
          :type resource_class_kwargs: dict
  
          Additional keyword arguments not specified above will be passed as-is
          to :meth:`flask.Flask.add_url_rule`.
  
          Examples::
  
              api.add_resource(HelloWorld, '/', '/hello')
              api.add_resource(Foo, '/foo', endpoint="foo")
              api.add_resource(FooSpecial, '/special/foo', endpoint="foo")