'Converts a v3 EntityProto to a v1 Entity.
Args:
v3_entity: an entity_pb.EntityProto
v1_entity: an googledatastore.Proto to populate'

def v3_to_v1_entity(self, v3_entity, v1_entity):

    v1_entity.Clear()
    self.v3_to_v1_key(v3_entity.key(), v1_entity.key)
    if (not v3_entity.key().has_app()):
        v1_entity.ClearField('key')
    for v3_property in v3_entity.property_list():
        self.__add_v1_property_to_entity(v1_entity, v3_property, True)
    for v3_property in v3_entity.raw_property_list():
        self.__add_v1_property_to_entity(v1_entity, v3_property, False)
