Error with Week 3 Exercise Grader: UNQ_C1

Hi,

I have completed the exercise for Week 3 and passed all tests in the notebook. When I run the grader, I get the following unhelpful error:
Comment line with index: UNQ_C1 wasn't found in code

Any thoughts as to how to fix this? Seems like some unexpected error in the grading system.

Hi,

Please add:

# UNQ_C1
# GRADED FUNCTION: sigmoid

To the top of the code cell where you define the sigmoid function.