error between instances of function and function in model.compile

Question

I tried to test the following colab project

https://colab.research.google.com/drive/1PXe6Wkhe1zXu8mXY7PMyW7l-rxZoSTRd?usp=sharing

I correct many errors, but I did not find any answer of the following error :

model.compile(loss='sparse_categorical_crossentropy',optimizer=opt,metrics=['accuracy'])
  File "/usr/local/lib/python3.10/dist-packages/keras/src/utils/traceback_utils.py", line 70, in error_handler
    raise e.with_traceback(filtered_tb) from None
  File "/usr/local/lib/python3.10/dist-packages/tensorflow/python/util/nest_util.py", line 727, in _tf_core_flatten
    return _pywrap_utils.Flatten(structure, expand_composites)
TypeError: '<' not supported between instances of 'function' and 'function'

This project is already tested using an old versions of tensorflow, keras ....as mentioned in env.txt file: https://github.com/erwei-xilinx/Enabling-Binary-Neural-Network-Training-on-the-Edge

Could you please help me to solve this problem.