Converts the column family to a protobuf.

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

def to_pb(self):
        """Converts the column family to a protobuf.

        :rtype: :class:`.table_v2_pb2.ColumnFamily`
        :returns: The converted current object.
        """
        if self.gc_rule is None:
            return table_v2_pb2.ColumnFamily()
        else:
            return table_v2_pb2.ColumnFamily(gc_rule=self.gc_rule.to_pb())