Comment by akx

This doesn't do the same thing though, since it's not Unicode aware.

    >>> 'x\u2009   a'.split()
    ['x', 'a']
    # incorrect; in bytes mode, `\S` doesn't know about unicode whitespace
    >>> list(re.finditer(br'\S+', 'x\u2009   a'.encode()))
    [<re.Match object; span=(0, 4), match=b'x\xe2\x80\x89'>, <re.Match object; span=(7, 8), match=b'a'>]
    # correct, in unicode mode
    >>> list(re.finditer(r'\S+', 'x\u2009   a'))
    [<re.Match object; span=(0, 1), match='x'>, <re.Match object; span=(5, 6), match='a'>]