@classmethod 
    def get_proxy_class(cls, base_type):
        class_map = dict(vertex=VertexIndexProxy, edge=EdgeIndexProxy)
        return class_map[base_type]
Sets and gets a custom property on the SIP container.
dataset/ETHPy150Open espeed/bulbs/bulbs/rexster/index.py/Index.get_proxy_class--crossover with--dataset/ETHPy150Open wsadminlib/wsadminlib/tests/wsadminlib.test.py/testSIPCustomProps