human
Complete the below
def _removeBackrefs(senderkey):

    ''''Remove all back-references to this senderkey'
    '''
 Give me a the Python code you requested?
assistant
#Here is the Python code you requested.
    try:
        signals = connections[senderkey]
    except KeyError:
        signals = None
    else:
        items = signals.items()
        def allReceivers():
            for (signal, set) in items:
                for item in set:
                    (yield item)
        for receiver in allReceivers():
            _killBackref(receiver, senderkey)