Rearrage order of python versions. Hopefully travisci runs versions in my specified order. Run non-dev current versions first. Latest ResourceWarning failures only show up in 3.8 and 3.9, so let them run during the first batch of 4 jobs. Then backfill with earlier versions and nightly versions. Note travis has 3.9-dev even though it's tracking a released version.

try:
    # Python 2.
    my_input = raw_input
except NameError:
    # Python 3+.
    my_input = input