Problem with tensor flow Notebook --> Failed test case: model has incorrect type. Expected: <class 'keras.engine.training.Model'>, but got: <class 'NoneType'>

Can you please post the error you are getting with screenshot image. There is another post related to this assignment which has solutions for this similar error. Kindly refer using search engine or post the screenshot here.

If your model is not defined with correct code and/or has not replaced all the None inside #START AND END CODE HERE, you will encounter such error.

Regards
DP