PYTHONPATH not working for sudo on GNU/Linux (works for root)

Question

EDIT: Works for root, sudo is the problem. Read below.

I have a directory with my own libraries, e.g. my Python libraries are located at /home/name/lib/py

Answer 1

The fix in my case was to remove Defaults !env_reset from sudoers.

But, I had to keep Defaults env_keep += "PYTHONPATH" in sudoers.
I've actually added Defaults env_reset (which resets environment variables), but it still works because of env_keep.

It seems that env_keep and !env_reset conflict with eachother, but that's just a guess.

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So, the whole process:

1. add export PYTHONPATH=/your/custom/path to ~/.bashrc or /etc/bash.bashrc
2. add PYTHONPATH to Defaults env_keep += "ENV1 ENV2 ..." in sudoers file
3. remove Defaults !env_reset from sudoers file if present