code: def to_pb(self):
          
          max_age = _helpers._timedelta_to_duration_pb(self.max_age)
          return table_v2_pb2.GcRule(max_age=max_age)
docs: Converts the garbage collection rule to a protobuf.
  
          :rtype: :class:`.table_v2_pb2.GcRule`
          :returns: The converted current object.