code: def liveReceivers(receivers):
      
      for receiver in receivers:
          if isinstance( receiver, WEAKREF_TYPES):
              # Dereference the weak reference.
              receiver = receiver()
              if receiver is not None:
                  yield receiver
          else:
              yield receiver
docs: Filter sequence of receivers to get resolved, live receivers
  
      This is a generator which will iterate over
      the passed sequence, checking for weak references
      and resolving them, then returning all live
      receivers.