import pickle
class F:
    def __init__(self,fileName):
         self = pickle.load(fileName)
         # let self.fileName be equal to fileName in this example.
    def __del__(self):
         pickle.dump(self.fileName, self)
    def miscMutatingMethod(self):
         ...

class F(autopickle):
    def __init__(self,filename):
         autopickleFilename = filename
         #now autopickle can do its work.
    def miscMutatingMethod(self):
         ...