Python

If you have to import a directory structure, you should make each directory a module by creating an __init__.py file in them, and use relative import statements. I usually have one main.py as the entry point, which imports a lib module that contains all of the program logic.

├── lib
│   ├── __init__.py
│   ├── module_content.py
│   └── submodule
│       ├── __init__.py
│       └── submodule_content.py
└── main.py

You can import the lib directory as a module:

main.py:

from lib import some_fn

Within any module, though, you should use relative import statements to import from files and submodules, and regular import statements to import packages from the system or the venv:

lib/__init__.py:

from .module_content import some_fn # import from a file
from .submodule import some_other_fn # import from a submodule directory
from os.path import join # import from an installed package

Items that you define in __init__.py or import into it will be available to import from the module: from .submodule import some_fn. Otherwise, you can import an item from a file by specifying the full path: from .submodule.submodule_content import some_fn.

You can also import an item from a parent package using the .. prefix: from ..some_other_submodule import some_fn.