Python Function keeps returing none [closed]

Question

I have a function that replaces all vowels when shown below, but when i go to use the function and print the output result, i get none

def replace_vowels(name):
    name.lower
    name.replace("a","*")
    name.replace("e","*")
    name.replace("i","*")
    name.replace("o","*")
    name.replace("u","*")
    name.replace("y","*")

celeb_1 = input("Enter the name of the first celeberty: ")
celeb_2 = input("Enter the name of the second celeberty: ")
celeb_3 = input("Enter the name of the third celeberty: ")
celeb_1_s = replace_vowels(celeb_1)
celeb_2_s = replace_vowels(celeb_2)
celeb_3_s = replace_vowels(celeb_2)
print (celeb_1_s)
print (celeb_2_s)
print (celeb_3_s)

The output result is:

Enter the name of the first celeberty: Elon Musk
Enter the name of the second celeberty: Donald Trump
Enter the name of the third celeberty: Bill Gates
None
None
None

Answer 1

You need to return the result of calling lower and replace; these don't mutate the string (strings are immutable). Chaining all the calls together it would look like:

def replace_vowels(name):
    return name.lower().replace(
        "a", "*"
    ).replace(
        "e", "*"
    ).replace(
        "i", "*"
    ).replace(
        "o", "*"
    ).replace(
        "u", "*"
    ).replace(
        "y", "*"
    )

Or you could re-assign each call's result to name and return it at the end:

def replace_vowels(name):
    name = name.replace("a","*")
    name = name.replace("e","*")
    name = name.replace("i","*")
    name = name.replace("o","*")
    name = name.replace("u","*")
    name = name.replace("y","*")
    return name.lower()

Or use an iteration instead of six calls to replace:

def replace_vowels(name):
    return ''.join("*" if c in "aeiouy" else c for c in name.lower())