That indicates that you must have modified parts of the template code that was given to you in a way that was not intended. Every graded cell has a couple of comment lines as the first lines in the cell that typically look something like this:
# UNQ_C1
# GRADED FUNCTION: compute_entropy
def compute_entropy(y):
You must have accidentally deleted or modified that first line. You can get a clean copy of the notebook to compare by following the instructions here. Or look at any of the other graded cells besides the first one or the cells in the Week 2 lab.