Python 3.11 made a traceback look like this:

    Traceback (most recent call last):
      File "{path}", line 8, in <module>
        print(sys.argv[1])
              ~~~~~~~~^^^
    IndexError: list index out of range

We needed to not care if that tilde-caret line was present or not.

On CPython 3.11, PyContracts fails on import, so we need to shut it off more
completely.

PyContracts is unmaintained these days, so we'll probably get rid of it
completely soon.