def METHOD_NAME(self, ext):
    ext = ext.lower()
    try:
        command = self.config['commands'].get(dict).get(ext)
    except confuse.NotFoundError:
        command = None
    if command:
        return self.check_custom(command)
    if ext == "mp3":
        return self.check_mp3val
    if ext == "flac":
        return self.check_flac