def __init__(self):
    super(ArtifactDefinitionsRegistry, self).__init__()
    self._artifact_definitions = {}
    self._artifact_name_references = set()
    self._defined_artifact_names = set()
Implementation of the PurgeQueue RPC.
dataset/ETHPy150Open ForensicArtifacts/artifacts/artifacts/registry.py/ArtifactDefinitionsRegistry.__init__--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/taskqueue/taskqueue_stub.py/_Group.PurgeQueue_Rpc