I am making a password generator. How do I make it that if the user enters **no** to the questions. no uppercase, for example. The generator sill works just without the uppercase?

```
   print("hello, Welcome to Password Generator")
            length = int(input('Please enter the length of password: '))
            upperanswer = input("Would you like to use UpperCase? ")
            if upperanswer == "yes":
                    upper = string.ascii_uppercase
            loweranswer = input("Would you like to use LowerCase?")
            if loweranswer == "yes":
                    lower = string.ascii_lowercase
            numberanswer = input("Would you like to use Numbers?")
            if numberanswer == "yes":
                    numbers = string.digits
            specialanswer = input("Would you like to use Special Characters?")
            if specialanswer == "yes":
                    special = string.punctuation
            all = lower + upper + numbers + special
            temp = random.sample(all,length)
            password = "".join(temp)
            print(password)

```