entity.py 文件源码

def _load_callback(callback_name):
        """
        Load a callback function by name and check its form (must have one parameter named "entity").
        :param callback_name: Name of the callback function to load.
        :return: The callback function.
        """
        try:
            callback_function = getattr(callbacks, callback_name)
            callback_parameters = signature(callback_function).parameters
            # check if callback has the correct form (only one parameter named "entity")
            if len(callback_parameters) == 1 and "entity" in callback_parameters:
                return callback_function
            else:
                raise IllegalArgumentError("Invalid callback: " + str(callback_name))
        except AttributeError:
            raise IllegalConfigurationError("Parsing configuration file failed: Callback "
                                            + callback_name + " not found.")