def get_versions(self, server):
    raise NotImplementedError()
Test that when a DelayedCall is cancelled it does not run.
dataset/ETHPy150Open AppScale/appscale/AppServer/google/appengine/api/request_info.py/Dispatcher.get_versions--crossover with--dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/test/test_internet.py/TimeTestCase.test_cancelDelayedCall