DLS C5W2 A2 Emoji Assignment Submission Grader faults on Cell 12

Cell #12. Can’t compile the student’s code. Error: TypeError(“unsupported operand type(s) for -: ‘NoneType’ and ‘float’”,)

I passed all the tests and submitted the assignment twice with a clean ipynb. I don’t know which cell is 12. I thought it was a test cell in EX 2 after restarting and executing all cells.
So, I am stumped on this one. Can anyone on staff help since you know the grader and I don’t.

Hi Gian,

If you send me your notebook I can have a look at what is going on.

Just did. Thank you for investigating this puzzle.

Thanks . I resubmitted it with a new kernel and it worked. Funny, because I restarted the kernel on my second try, knowing that the grader can be temperamental.