Return a list of bytes representing the function descriptor.

        This function is used to pass this function descriptor to backend.

        Returns:
            A list of bytes.

def get_function_descriptor_list(self):
        """Return a list of bytes representing the function descriptor.

        This function is used to pass this function descriptor to backend.

        Returns:
            A list of bytes.
        """
        descriptor_list = []
        if self.is_for_driver_task:
            # Driver task returns an empty list.
            return descriptor_list
        else:
            descriptor_list.append(self.module_name.encode("ascii"))
            descriptor_list.append(self.class_name.encode("ascii"))
            descriptor_list.append(self.function_name.encode("ascii"))
            if len(self._function_source_hash) != 0:
                descriptor_list.append(self._function_source_hash)
            return descriptor_list