def __init__(self, names=None):
    if not names:
      raise errors.FormatError(u'Missing names value.')

    super(ArtifactGroupSourceType, self).__init__()
    self.names = names
Returns:
dataset/ETHPy150Open ForensicArtifacts/artifacts/artifacts/source_type.py/ArtifactGroupSourceType.__init__--crossover with--dataset/ETHPy150Open meraki-analytics/cassiopeia/cassiopeia/type/core/league.py/Entry.losses