Why is there a "ModuleNotFoundError" error when running a .py file via cmd?

Question

Python

The error ModuleNotFoundError: No module named '...' is thrown. I realized from the error that he does not see the AATC folder, although the main launch file is located there.
I want to understand what causes this error and how to get rid of it.
My project uses a python file that calls another .py file.


Thanks in advance.