I feel like it should work, but Python doesn't seem to care about my feelings. So I'm playing around with functions and I feel like I should be able to create a function that returns a boolean value that breaks a while loop in the body of the code. So here's what I've got, sadly, it doesn't seem to actually read what's being returned and just continues to ask for a username. Please, ignore my stupid usernames, I am neither smart no clever. :

def username_checker(username, users,):
    """Checks list of users to find out if username is already taken"""
    if username in users:
        print("\nSorry that name is already taken.")
        return True

    else:
        print (f"\nWelcome, {username}")
        return False
        

users = ["bbrad", "poopinajimmyhat7", "coolkid28",]
while True:
    user_name = input ("\nPlease enter a username: ")
    username_checker (user_name, users)

Hello I am doing Jose Portillas course on python in udemy and I ran into a bit of code that I am having a hard time wrapping my head around.

def summer_69(arr):
    sum69 = 0 
    cond = True
    for num in arr:
        while cond: 
            if num != 6: 
                sum69 += num
                break
            else: 
                cond = False
        while not cond: 
            if num != 9: 
                break
            else:
                cond = True
                break
summer_69([2, 1, 6, 9, 11])

as you can see the variable cond starts with True assigned to it. but in the first while loop if the condition is no longer met (that the variable num is not equal to 6) then the cond will have its value reassigned to False.

so if cond is now false. how come it skips the first while loop considering that the while loops condition is met in the next iteration

and also why, in the second while loop, does it meet the conditions is the variable assigned to cond somehow still True?