gistfile1.py

class ParallelWorker(threading.Thread):
    
    def __init__(self, cb, fn, args, kwargs):
        self._cb = cb
        self._fn = fn
        self._args = args
        self._kwargs = kwargs
        super(ParallelWorker, self).__init__()
    
    def run(self):
        result = self._fn(*self._args, **self._kwargs)
        cb = functools.partial(self._cb, result)
        ioloop.IOLoop().instance().add_callback(cb)


def parallel(fn):
    
    def wrapper(*args, **kwargs):
        callback = kwargs.pop("callback")
        worker = ParallelWorker(callback, fn, args, kwargs)
        worker.start()
    
    def decor(*args, **kwargs):
        return gen.Task(wrapper, *args, **kwargs)
    
    return decor