Question: Structure and debug a package with multiple subpackages

Hello,

I have a package with multiple subpackages that I want to correct.

For troubleshooting my package, i would be interested by 2 points :
1) I would like use subsection for each subpackage. It would enable to have a better view of the structure of my package. However, I heard that sections, and subsections can lead to syntax errors. Is there a possibility to gather lines in a subpackages as with a section or subsection ?

2) To troubleshoot my package, I would like to comment a important part of code lines. Is there a technique to comment/ uncomment an important group of lines in the same time. I would enable me to valid my code little by little.

Thanks a lot for your help and tips so as to troubleshoot a big package with many subpackages.