testdeco.py

import functools
import time
import pickle
import os

def decorator(save_path="default"):
    def wrapper(fn):
        @functools.wraps(fn)
        def wrap(self, *args, **kwargs):
            if not os.path.exists(save_path):
                o = fn(self, *args, **kwargs)
                with open(save_path, "wb") as h:
                    pickle.dump(o, h)
            with open(save_path, "rb") as h:
                return pickle.load(h)
        return wrap
    return wrapper

class Foo(object):
    @decorator(save_path="/home/gilesc/test.pkl")
    def myfunc(self):
        time.sleep(3)
        return "xyz"

if __name__ == "__main__":
    obj = Foo()
    print(obj.myfunc())