A faster interpreter, more intelligible errors, more powerful type hints, and a slew of other speedups and tweaks are now ready to try out. The Python programming language releases new versions yearly ...
(see: http://diveinto.org/python3/porting-code-to-python-3-with-2to3.html#next; looks like item number 4 may be backwards compatible) ...it works fine, but I'm not ...
ERROR: Ignored the following versions that require a different python version: 0.55.2 Requires-Python <3.5; 2.10.1 Requires-Python <3; 2.11.0 Requires-Python <3; 2.11 ...