All tests pass, all outputs match, but grader complains about "hidden cells"

Yes, it is unfortunate that the grader cannot say anything more specific than that. Believe me, we have pointed this out to the course staff as being (how shall we say) “unhelpful” but apparently this is a limitation of the grader platform as provided by Coursera. Sigh …

It would be nice if you could specify which assignment you’re talking about when you make a post like this, but fortunately there are enough clues in the grader output to see that it’s the Tensorflow Introduction assignment in Course 2 Week 3.

One thing to be aware of is that they have published a new version of this assignment just a few days back and then there was a fix to the new version. The first thing to check is that you’ve got the latest version. An easy way to check is to compare the “Expected Value” for the compute_cost function. The latest version should show this value:

Expected output

tf.Tensor(0.4051435, shape=(), dtype=float32)

If that’s not what you see there, then the first step is to upgrade to the latest. There’s a topic about that on the FAQ Thread.

If you have the latest version, I assume you’ve double checked to make sure you pass all the tests in the notebook.