'Register a text key.
If the key you need to register is a simple one-to-one mapping
of ID3 frame name to EasyID3 key, then you can use this
function::
EasyID3.RegisterTextKey("title", "TIT2")'

@classmethod
def RegisterTextKey(cls, key, frameid):

    def getter(id3, key):
        return list(id3[frameid])
    def setter(id3, key, value):
        try:
            frame = id3[frameid]
        except KeyError:
            id3.add(mutagen.id3.Frames[frameid](encoding=3, text=value))
        else:
            frame.encoding = 3
            frame.text = value
    def deleter(id3, key):
        del id3[frameid]
    cls.RegisterKey(key, getter, setter, deleter)
