def METHOD_NAME(self, obj):
    __date_time_null_value__ = 2**64 - 1
    if obj.time == __date_time_null_value__:
        return ""
    if obj.HasField('date'):
        return timestamp_to_str(obj.date + obj.time)
    return datetime.utcfromtimestamp(obj.time).strftime('%H%M%S')