Python3 codeclub.py.
Merge branch 'airport-problem' into stage-3-solution
Merge branch 'stage-3-solution' into stage-4-solution
Merge branch 'stage-4-solution' into stage-5-solution
Merge branch 'stage-5-solution' into stage-6-solution
Merge branch 'stage-6-solution' into stage-7-solution
Merge branch 'stage-7-solution' into stage-8-solution
Python3 tweak.