Cell #9. Can't compile the student's code. Error: NameError("name 'mu' is not defined")

Course Q&A Machine Learning Specialization Unsupervised Learning, Recommenders, Reinforcement
1

lab id:-
cacqyycvlajl

2

It appears you have a variable named “mu” in one of your functions that is not defined.

You may need to run all of the cells in the notebook as soon as you open it.

3

Can you say a bit more about when this issue occurs? You didn’t provide very many clues.

4

Today I opened my notebook, and all my code which I have written is no more.
I think my code has not been saved, because of which it might be given this error.

Now it is resolved.

Thank you.