C1_W3_Assignment. Part 3.4

Hi, I am having difficulties after part 3.4. It says, " Go through the code in section [2] and see that if you pass new datasets X_multi_norm and Y_multi_norm, the input layer size n_x will get equal to 2 and the rest of the implementation will remain exactly the same" According to this, I went section 2 and changed inputs as X_multi_norm and Y_multi_norm. But if you keep the rest of the things the same, it gives dimension problems.
Do I need to go to section 2 and change inputs? Then I need to proceed with everything again, according to the new inputs? It is really not clear to me. Thank you in advance.

No. This section is optional and make changes if you want to play around with your own datasets. The section just tries to emphasize on the fact that you could reuse the same code for different dataset(s).