Draw a diamond on the screen the size that the user wants

diamond.py

def is_number_input(user_input):
    if not user_input.isnumeric():
        print("You must input a whole number!")
        return 0
    user_input = int(user_input)
    if user_input > 35:
        print("Your number must be smaller than 35!")
        return 0
    elif user_input < 2:
        print("Your number must be larger than 1!")
        return 0
    return user_input


def is_yes_no_input(input):
    if input.lower() == "yes" or input.lower() == "y":
        print("Yay!")
        return True
    else:
        print("I'll take that as a no!, Goodbye!")
        return False


def draw_diamond_top(num):
    for x in range(1, num + 1):
        spaces = num - x
        for y in range(0, spaces):
            print(" ", end="")
        for z in range(0, x):
            print("* ", end="")
        print()


def draw_diamond_bottom(num):
    for x in reversed(range(1, num)):
        spaces = num - x
        for y in range(0, spaces):
            print(" ", end="")
        for z in range(0, x):
            print("* ", end="")
        print("")


def main():
    again = True
    while again is True:
        user_input = input("What width diamond would you like? ")
        valid_input = is_number_input(user_input)
        if valid_input == 0:
            continue
        draw_diamond_top(valid_input)
        draw_diamond_bottom(valid_input)
        go_again = input("Would you like to draw another diamond? ")
        again = is_yes_no_input(go_again)


if __name__ == "__main__":
    main()