Converts string datetime in ISO format to protobuf timestamp.
    :type dt: str
    :param dt: string with datetime in ISO format
    :rtype: :class:`~google.protobuf.timestamp_pb2.Timestamp`
    :returns: protobuf timestamp

def proto_ts_from_datetime_str(dt):
    """Converts string datetime in ISO format to protobuf timestamp.
    :type dt: str
    :param dt: string with datetime in ISO format
    :rtype: :class:`~google.protobuf.timestamp_pb2.Timestamp`
    :returns: protobuf timestamp
    """

    ts = Timestamp()
    if (dt is not None):
        try:
            ts.FromJsonString(dt)
        except ParseError:
            pass
    return ts