Python Arithmetic Formatter problem

Can somebody help me? I got “Expected different output when calling” error during the test running and I have no idea what is the difference between my output and the expected one. It looks like totally the same to me. How can I find the difference?

My result url:


please give your repl link so it is possible to see your code

the only thing I can see from the tests is that your function returns None

Here is my code:

Thank you!

I figured it out when you wrote “function returns None”, I did not have a return statement. I had to change the print function to return, and it worked. Thank you for your help!