def disconnect_all(signal=Any, sender=Any):
    """Disconnect all signal handlers. Useful for cleaning up after running
    tests
    """
    for receiver in liveReceivers(getAllReceivers(sender, signal)):
        disconnect(receiver, signal=signal, sender=sender)
Disconnect all signal handlers. Useful for cleaning up after running
    tests
    
stackoverflow/venv/lib/python3.6/site-packages/scrapy/utils/signal.py