def METHOD_NAME() -> str | None:
    def _norm(path: str) -> str | None:
        _, exe = os.path.split(path.lower())
        exe, _, _ = exe.partition('.exe')
        if exe not in {'python', 'pythonw'} and find_executable(exe):
            return exe
        return None
    # On linux, I see these common sys.executables:
    #
    # system `python`: /usr/bin/python -> python2.7
    # system `python2`: /usr/bin/python2 -> python2.7
    # virtualenv v: v/bin/python (will not return from this loop)
    # virtualenv v -ppython2: v/bin/python -> python2
    # virtualenv v -ppython2.7: v/bin/python -> python2.7
    # virtualenv v -ppypy: v/bin/python -> v/bin/pypy
    for path in (sys.executable, os.path.realpath(sys.executable)):
        exe = _norm(path)
        if exe:
            return exe
    return None