date parsing rebased on extracted method - combining #180+#178

[okurz]

This is

• Don't crash in case of unexpected build date format #178
  rebased onto
• approver: Extract function 'was_older_job_ok' #180

[okurz]

@michaelgrifalconi ok like this?

[michaelgrifalconi]

I still feel it got more complicated just to please the formatting rules, but looks overall fine.
Nice thing the return None, was not aware of that.
Thank you!

[okurz]

I still feel it got more complicated just to please the formatting rules, but looks overall fine.

It's important to just agree on styling rules, enforce them with automation and stick to it. If you feel in general a rule should be changed I suggest you propose that in a separate pull request but chances are slim we will agree on diluting the upstream python community rules