@needs_zmq
def register_message_handler(subject, callback):
    _handlers.setdefault(subject, []).append(callback)
get() -> return TestClass's associated value.
dataset/ETHPy150Open manahl/mdf/mdf/remote/messaging.py/register_message_handler--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.2/django/test/_doctest.py/_TestClass.get