code: def patch(self, resource_id):
          
          resource = self._resource(resource_id)
          error_message = is_valid_method(self.__model__, resource)
          if error_message:
              raise BadRequestException(error_message)
          if not request.json:
              raise BadRequestException('No JSON data received')
          resource.update(request.json)
          db.session().merge(resource)
          db.session().commit()
          return jsonify(resource)
docs: Return an HTTP response object resulting from an HTTP PATCH call.
  
          :returns: ``HTTP 200`` if the resource already exists
          :returns: ``HTTP 400`` if the request is malformed
          :returns: ``HTTP 404`` if the resource is not found
          :param resource_id: The value of the resource's primary key