I've had a quick look at pipe_drivers and it looks like the port to python 3 will be pretty easy: a couple of old-style exceptions, some use of itervalues(), other minor tweaks.

Currently lsst_distrib works fine regardless because there are no tests in pipe_drivers to fail (DM-9059).

I want to do this before the fixes for pybind11 DM-8462

A standard port. Pretty easy. One minor point: I ran autopep8 without the default line length because we are switching to 80 character lines. However, I was not religious about fixing any remaining lines that were longer. Call it a start in that direction.

Can you make a pull request? There are some extra list() calls that you don't need.

I removed all unnecessary list(...) and .keys(). I also found two more instances of foo = lambda that I turned into normal functions and added one # noqa to hide a linter warning caused by standard_library.install_aliases() being needed before some module-level import statements.

The lack of tests is a worry but these cleanups look fine to me. I'm happy to call this reviewed if Paul Price is too busy.

Marking "reviewed" as per Tim Jenness's comments above. Note that I also ran constructBias.py successfully under python 2, so at least that did not get broken by these changes.

Rebased to clean up the commit history a bit and merged.