I couldn’t pass the assignment, because is showing me an error in the grader output:
‘There was a problem compiling the code from your notebook. Details:
name ‘prices_A’ is not defined’
I double checked and the varialbe was defined with that name.
Did you perhaps delete one of the code cells, and then try to re-insert it?
Or, maybe you downloaded the notebook to work on some other platform, then uploaded it back to Coursera for grading?
Either of these will erase the cell metadata, which the grader uses to know which cells to inspect.
Do you know how to reset everything in the notebook, and leave it as it was before I started working in it?
Maybe, in that way I could get metadata back.
You can get a new copy and start over on the assignment.
See the “Topic 1b” item in the M4ML FAQ: