def ListFields(self):
    raise NotImplementedError
Ensures that given function is a generator function,
dataset/ETHPy150Open AppScale/appscale/AppServer/google/net/proto2/python/public/message.py/Message.ListFields--crossover with--dataset/ETHPy150Open Xion/pyqcy/pyqcy/properties.py/Property.__coerce_to_generator_func