Is there a way to return literally nothing in python?

There is no such thing as “returning nothing” in Python. Every function returns some value (unless it raises an exception). If no explicit return statement is used, Python treats it as returning None.

So, you need to think about what is most appropriate for your function. Either you should return None (or some other sentinel value) and add appropriate logic to your calling code to detect this, or you should raise an exception (which the calling code can catch, if it wants to).