My call back & Convolutional grading error

[maclearnpractice]

Dear Fellow learner

I have tested my code and it run as expected but when I submit it I have got below grading error
. Call back
There was a problem grading your submission. Details:
issubclass() arg 1 must be a class
. Convolutional Model
There was a problem grading your submission. Details:
‘NoneType’ object is not iterable

I have tried to refresh my notebook, check meta data and many others but it is still failed
I contacted Coursera Customer Service but they ask me to refer to this forum only

Please shed a light

William

[snippet deleted by mentor]

[balaji.ambresh]

Here are some hints:

1. The metric to look for when deciding when to stop training should not be acc.
2. The custom callback class should be named myCallback and not mycallback

[maclearnpractice]

Thank you so much Balaji sir,
it worked and I passed

William