Plugins for a Python program

[OldAl]

I am impressed with Bazaar's implementation of plugins: a Python
plugin is simply copied to a ./bazaar/plugin/<my-plugin> directory and
the plugin is recognized by Bazaar and can be run from CLI as:

bzr <my-plugin>

I would like to implement something similar in my Finite Element
Method program, so that any user can write certain element properties
(in a predetermined format) to use with the program.

The references that I looked at seem to use "distutils" as part of the
plugin installation.  Would you recommend to go  in that direction?
Any other good references?

BTW, the FEM program is currently designed to solve Engineering
structure analysis with the implemented elements for beams (frame
members) or truss members for 2D structures and also trusses in 3D
structures.

OldAl
PS: Trust me, I am really, really old...