Converts the garbage collection rule to a protobuf.

        :rtype: :class:`.table_v2_pb2.GcRule`
        :returns: The converted current object.

def to_pb(self):
        """Converts the garbage collection rule to a protobuf.

        :rtype: :class:`.table_v2_pb2.GcRule`
        :returns: The converted current object.
        """
        max_age = _helpers._timedelta_to_duration_pb(self.max_age)
        return table_v2_pb2.GcRule(max_age=max_age)