Necessary fixes for code regarding MNIST & FMNIST datasets

[aditya4567uk]

Hi there!

I am an active open source contributor and would like to contribute in your project, recently I was working on your project and found out that this NOT EXECUTING for MNIST & FMNIST dataset as it should be . I have a way to fix it and make it work. and one thing it's also giving error while saving checkpoint files(.ckpts) basically it's a path error and I can fix that too.

Could you pls assign me this issue.