def _play_sound_osx(sound, block=True):
    """
    Utilizes AppKit.NSSound. Tested and known to work with MP3 and WAVE on
    OS X 10.11 with Python 2.7. Probably works with anything QuickTime supports.
    Probably works on OS X 10.5 and newer. Probably works with all versions of
    Python.
    Inspired by (but not copied from) Aaron's Stack Overflow answer here:
    http://stackoverflow.com/a/34568298/901641
    I never would have tried using AppKit.NSSound without seeing his code.
    """
    from AppKit import NSSound
    from Foundation import NSURL
    from time import sleep
    if '://' not in sound:
        if not sound.startswith('/'):
            from os import getcwd
            sound = getcwd() + '/' + sound
        sound = 'file://' + sound
    url = NSURL.URLWithString_(sound)
    nssound = NSSound.alloc().initWithContentsOfURL_byReference_(url, True)
    if not nssound:
        raise IOError('Unable to load sound named: ' + sound)
    nssound.play()
    if block:
        sleep(nssound.duration())
