The platform module contains various version checks for systems such as cpython and ironpython. The file also contains a specfic case for ironpython which can be removed (see IronLanguages/ironpython3#1667)

Removing the check improves the import speed as it avoids the compilation of a two regular expressions.

%timeit _ironpython26_sys_version_parser = re.compile(r'([\d.]+)\s*'   r'\(IronPython\s*'    r'[\d.]+\s*'    r'\(([\d.]+)\) on ([\w.]+ [\d.]+(?: \(\d+-bit\))?)\)' )
383 ns ± 1.66 ns per loop (mean ± std. dev. of 7 runs, 1,000,000 loops each)

Note: most of the compiled regular expressions in platform.py can be moved into the methods using them, as most results are cached. This would reduce the importtime for platform even further:

Main: The speed of "import platform" is: 8.231517 +- 0.499458 [ms]
Regular expressions adapted: The speed of "import platform" is: 7.182120 +- 0.726896 [ms]

• Issue: Remove legacy ironpython 2 version check #102491