code: def _cleanupConnections(senderkey, signal):
      
      try:
          receivers = connections[senderkey][signal]
      except:
          pass
      else:
          if not receivers:
              # No more connected receivers. Therefore, remove the signal.
              try:
                  signals = connections[senderkey]
              except KeyError:
                  pass
              else:
                  del signals[signal]
                  if not signals:
                      # No more signal connections. Therefore, remove the sender.
                      _removeSender(senderkey)
docs: Delete any empty signals for senderkey. Delete senderkey if empty.