Add frame to the end of the message, i.e. after all other frames.
Message takes ownership of frame, will destroy it when message is sent.
Returns 0 on success. Deprecates zmsg_add, which did not nullify the
caller's frame reference.

def append(self, frame_p):
        """
        Add frame to the end of the message, i.e. after all other frames.
Message takes ownership of frame, will destroy it when message is sent.
Returns 0 on success. Deprecates zmsg_add, which did not nullify the
caller's frame reference.
        """
        return lib.zmsg_append(self._as_parameter_, byref(zframe_p.from_param(frame_p)))