You can mutate closed-over variables in Python. Here's an example.... def some_function(val): def say_stuff(): print("message is: {}".format(val)

You can mutate closed-over variables in Python. Here's an example.... def some_function(val): def say_stuff(): print("message is: {}".format(val)) def mutate_me(new_mutation): nonlocal val val = new_mutation say_stuff.mutate_me = mutate_me return say_stuff if __name__ == '__main__': f = some_function("hello") f.mutate_me("goodbye") f()