Repairing Python installation?

[Martin Schöön]

It seems something is amiss with my Python 2.7 installation. Revisiting
Nikola (static web site generator written in Python) for the first time
in several years the other day I experience some unexpected problems. I
got some help form the Nikola people and the conclusion is something
is broken with my Python 2.7. Pip list throws exceptions at me while
pip3 list works the way I expect it to do.

All this is happening on a Debian machine.

Questions:

Should I try to pinpoint what is broken (and how is that done) or should
I just remove everything Python 2.7 and re-install?

Could mixing pip installs with Debian distro installs of Python
packages lead to conflicts or other problems?

TIA,

/Martin