@khichi if you see the below pinned comment, you will see how the grade cell looks when you get a fesh copy of assignment.
you seem to have edited parts of codes which you are not suppose to.
when you next get a fresh copy of assignment, make sure just to replace the None with correct codes placed between the markers ###START AND END CODE HERE###
do not add any import statement in grade cell codes.
Also amke sure to read the comment in the same post for change in dimension codes as that is the usual point of mistake by most learners.
In the one hot encode the categories, num_classes=num_classes should be used, rather than what you have used.
Let me know if you need any help further, or send me how you did correction after this(make sure to send codes only by personal DM and not post here)
Regards
DP