Thanks for this note I think I need it since the grader didn’t pass my assignment.
But I didn’t mean the grader function first, my problem was with the code itself, the last part of the assignment is " Run the TensorFlow.js Converter on The Saved Keras Model"
I figured out the solution and used this code instead and it worked.
!tensorflowjs_converter --input_format keras \
"./my_model.h5"\
"./model"