Hi there,
I am currently attempting the programming assignment for course 1, week 2. I have passed all tests for propagate(), however, when this function is called in model() I get the error below:
I have been trying to debug for a while but with no luck.
Apologies, I found a similar issue which someone else had. Turns out I was not including “num_iterations” and “learning_rate” as arguments to optimize() within model().
No worries! Thanks for searching the archive. It will helps us to better allocate our time. 
