The upstream bash-completion package contains completions for some Python commands, including python*, pyvenv* and possibly more. At the same time, it hardcodes possible suffixes, resulting in absurds like installing it for 3.4 and 3.5 but not 3.6.
We should either:
1. add PYTHON_TARGETS and create symlinks for all versions explicitly,
2. move all the Python stuffs into a separate package and maintain it there.