Install packages without pip

I’m working on developing additions to a Ubuntu-based Thinclient. On this closed platform, I have no ability to use apt, dpkg, pip, … to install packages. In some projects, I came to a situation where I have to add missing python packages to the system. Python (2.7 and 3.8) is available.
The content of the packages will be available on the system.
Is there a way to make them part of the install without using pip?

If they’re pure python (no compilation phase) you can just copy them
into the site-packages area or even better, some directory you just add
to your $PYTHONPATH.

More elaborate packages may require you to run their setup.py files.

You could possibly also use “pip install” outside the system, then copy
the resulting tree into your system.

Cheers,
Cameron Simpson cs@cskk.id.au