Take into account that a label has been renamed

def rename(self, old_label_name, new_label_name):
        """
        Take into account that a label has been renamed
        """
        assert(old_label_name != new_label_name)
        self._bayes.pop(old_label_name)
        old_baye_dir = self._get_baye_dir(old_label_name)
        new_baye_dir = self._get_baye_dir(new_label_name)
        logger.info("Renaming label training {} -> {} : {} -> {}".format(
            old_label_name, new_label_name, old_baye_dir, new_baye_dir
        ))
        os.rename(old_baye_dir, new_baye_dir)