[$] Python 3.9 is around the corner

Python 3.9.0rc2 was released on September 17, with the final version scheduled for October 5, roughly a year after the release of Python 3.8. Python 3.9 will come with new operators for dictionary unions, a new parser, two string operations meant to eliminate some longstanding confusion, as well as improved time-zone handling and type hinting. Developers may need to do some porting for code coming from Python 3.8 or earlier, as the new release has removed several previously-deprecated features still lingering from Python 2.7.