def _wait_timeout(request):
    if not hasattr(request, "_in_do"):
        # Don't deal with requests that were closed. Just don't.
        return

    # Get the item off the top of the waiting stack, and make sure it's
    # something we can work with.
    if not request._waiting or not isinstance(request._waiting[-1], _WaitList):
        return

    # Build the input list.
    input = []
    for key in request._waiting.pop():
        value = request._callbacks.pop(key)
        input.append(value if value is not Waiting else None)

    # Now, pass it along to _do. Note the as_exception=True.
    _do(request, TimeoutError(input), as_exception=True)
Failed snapshots are not added to the list of snapshots.
dataset/ETHPy150Open ecdavis/pants/pants/web/asynchronous.py/_wait_timeout--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/volume/test/test_filesystems_memory.py/CannedFilesystemSnapshotsTests.test_failed