Helper method for special keys.

    Source: http://stackoverflow.com/questions/11045814/emulate-media-key-press-on-mac

def _specialKeyEvent(key, upDown):
    """ Helper method for special keys.

    Source: http://stackoverflow.com/questions/11045814/emulate-media-key-press-on-mac
    """
    assert upDown in ('up', 'down'), "upDown argument must be 'up' or 'down'"

    key_code = special_key_translate_table[key]

    ev = AppKit.NSEvent.otherEventWithType_location_modifierFlags_timestamp_windowNumber_context_subtype_data1_data2_(
            Quartz.NSSystemDefined, # type
            (0,0), # location
            0xa00 if upDown == 'down' else 0xb00, # flags
            0, # timestamp
            0, # window
            0, # ctx
            8, # subtype
            (key_code << 16) | ((0xa if upDown == 'down' else 0xb) << 8), # data1
            -1 # data2
        )

    Quartz.CGEventPost(0, ev.CGEvent())