A picklable type that calls a function when unpickled.

pickled_call.py

class PickledCall:
    def __new__(cls, to_call, args=(), kwargs=None, __pickle_target=None):
        if __pickle_target is None:
            result = super(cls, PickledCall).__new__(cls)
            result.to_call = to_call
            result.args = args
            result.kwargs = kwargs or {}
            return result
        else:
            return __pickle_target(*args, **kwargs)
    
    def __getnewargs__(self):
        return (None, self.args, self.kwargs, self.to_call)


import pickle

class Gold:
    
    def __init__(self, item):
        self.item = item
    
    def announce(self):
        print(f'Golden {self.item}!')
        
pickled_call = pickle.dumps(PickledCall(Gold, ('crown',)))
print(pickled_call)
result = pickle.loads(pickled_call)
result.announce()