code: def init_blueprint(self, blueprint):
          
          if self._route is not None:
              raise TypeError("route cannot be set when using blueprints!")
  
          blueprint.rak = self
          blueprint.add_url_rule("", view_func=getattr(self, self._view_name), methods=['POST'])
docs: Initialize a Flask Blueprint, similar to init_app, but without the access
          to the application config.
          Keyword Arguments:
              blueprint {Flask Blueprint} -- Flask Blueprint instance to initialize (Default: {None})