def assertPbIsInitialized(self, pb):
    explanation = []
    assert pb.IsInitialized(explanation), explanation

    pb.Encode()
Raises an exception if the given PB is not initialized and valid.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/datastore_file_stub.py/DatastoreFileStub.assertPbIsInitialized