GraphQL\Validator\Messages::reasonMessage PHP Method

    private static function reasonMessage($reason)
    {
        if (is_array($reason)) {
            $tmp = array_map(function ($tmp) {
                list($responseName, $subReason) = $tmp;
                $reasonMessage = self::reasonMessage($subReason);
                return "subfields {$responseName} conflict because {$reasonMessage}";
            }, $reason);
            return implode(' and ', $tmp);
        }
        return $reason;
    }