How come the global variable is not returned despite keyword global being used

Question

I have accessed a global variable called counter using the keyword global however the function does not return the global variable. Oddly, print works but not return.

FYI: The function below is recursive and is supposed to take as input any integer and output the number of steps required to reduce it to 0, depending on whether it's odd or even at each iteration.

counter = 0
def number_of_steps(num):
    global counter
    if num == 0:
        return(counter)
    elif num % 2 == 0:
        num = num / 2
        counter += 1
        number_of_steps(num)
    else: 
        num -= 1
        counter += 1
        number_of_steps(num)
 
number_of_steps(2) #expect => 2, but actually get NoneType

Answer 1

As pointed out by @tripleee this is a duplicate of this post

In short, Python implicitly returns None if a return statement is not added.