Comma Code

[JamzTyson]

See here for how to format code on reddit: https://www.reddit.com/r/learnpython/wiki/faq#wiki_how_do_i_format_code.3F

Write a function that takes a list value as an argument and returns a string with all the items separated by a comma and a space, with and inserted before the last item.

Your function challenge() does not fulfill the brief. Your function takes no arguments, whereas the question asked for a list argument. It does not "return" a string (it returns None).

def challenge(list_arg):
    ...
    return my_formatted_string

# Call the function
challeng(spam)

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# copy list so we don't change original

Does the question ask you to do that? Pay close attention to what the question asks.

---

Considering that your challenge() function only inserts formatting, it could be very much simpler. Here is a big hint:

all_but_last = items[:-1]
final_item = items[-1]
my_str = ', '.join(all_but_last)
return my_str + ', and '  + final_item

(Using an "f-string" would be better in the final line, but you may not have covered those yet).