Getting 'Failed to test your code.' message

I am doing the Python Heaps module: 5. Adding an element: Heapify Up II and for some reason when I get to step 4, my code does not run. I’ve tried to reset the exercise and it stalls again at the same point. Has any one else been experiencing this or is it a known issue?

Course URL:


Please can you paste in your code so that I may test it on my end as I can’t seem to reciprocate the error, perhaps its displaying an incorrect error message.