def METHOD_NAME(func):
    """Runs a thing once and once only."""
    lock = threading.Lock()
    def new_func(*args, **kwargs):
        if new_func.called:
            return
        with lock:
            if new_func.called:
                return
            rv = func(*args, **kwargs)
            new_func.called = True
            return rv
    new_func = update_wrapper(new_func, func)
    new_func.called = False
    return new_func