'Returns an Artist for the passed ID, associated with this API object. You\'ll need to call Artist.update_data()
if the artist hasn\'t already been cached. This is done on demand to reduce unnecessary API calls.'

def get_artist(self, id=None, name=None):

    if id:
        id = int(id)
        if (id in self.cached_artists.keys()):
            artist = self.cached_artists[id]
        else:
            artist = Artist(id, self)
        if name:
            artist.name = HTMLParser().unescape(name)
    elif name:
        artist = Artist((-1), self)
        artist.name = HTMLParser().unescape(name)
    else:
        raise Exception('You    must    specify    either    an    ID    or    a    Name    to    get    an    artist.')
    return artist
