C5W1A2 - Appear error when submit: Unexpected error (KeyError('da_next')) occurred during function check. We expected function `optimize` to return Test 3 failed. Please check that this function is defined properly

I saw that gradient given in optimize have 6 elements, including data_next. However, i can’t access that key (manually). Can you please help me?

Exercise optimize i have past. I have a problem with Last exercise while my answer is 0.294620.

I found there are questions have same problems with me. I have restart kernel, clear output and run all but it’s not work.

After one day of code, i found my error for answer 0.2946. Student should read instruction step 1 again :rofl: