Recommender systems error

How to debug errors in tests? specifically, in Recommender Systems (Collaborative Filtering) test_cofi_cost_func fails but my implementation of cofi_cost_func passes (produces correct output)

The test cases are not wrong. Most likely there is an error in your code.

understood – however, to check this I literally copied the code in the “hints” for cofi_cost_func – and I get the same error in test_cofi_cost_func

Perhaps you have not implemented the hints correctly.

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