public static function formatConditions($methondname, $conditions)
    {
        if (count($conditions) > 1) {
            throw new InvalidArgumentException(
                sprintf("Method '%s' supports a single array input", $methondname)
            );
        }

        if (1 == count($conditions)) {
            if ($conditions[0] instanceof Node) {
                return $conditions;
            }
        }

        $conditions = (empty($conditions)) ? [[]] : $conditions;

        return call_user_func_array('array_merge', $conditions);
    }