¿Qué cambio se requiere en el código fuente?

    def Update():
        print('\n')
        print("Update")
        cmd = os.system('xterm -e apt-get update')
        print("Finish update")

    def AptUpdate():
        print('\n')
        print("Update system? {Y/N}")
        print("Y or y")
        print("N or n")
        code = input("Command > ")
        if code == 'y' or code == 'Y':
            for i in Update():
                return Update
            elif code == 'n' or code == 'N': 
                return 
            else: 
                print("Warning!")

    AptUpdate()

    exception:

    Traceback (most recent call last):
      File "pybash.py", line 110, in 
        AptUpdate()
      File "pybash.py", line 102, in AptUpdate
        for i in Update:
    TypeError: 'function' object is not iterable