Well, I don't see where you declared new_names, so it's not surprising. But ok, let's say you did. Then, new_names = new_names.append(...) - I really don't know how this should work, and it probably doesn't. My guess is that .append() returns None, so you re-assigned new_names to None.

Yeah I was just printing it for debugging purposes. You can see the rest of my solution,but when I go on to iterate through new_names after using the second method it doesn't work because it is a NoneType

You need to return the result, not print it.

Please don't post solutions to the discourse section, and if you must, use the spoiler flag.

As for your question: Python code is nearly impossible to properly parse without proper formatting. Use Markdown to format your code. Also when you run the tests, they will typically tell you what is wrong with your result, i.e. what you returned and what was expected.