private bool WriteSingleFile(LanguageData data, string dstPath)
        {
            var root = new JObject();

            var groups = data.GroupBy(o => o.Namespace);
            foreach (var g in groups)
            {
                var namespaces = g.Key.Split('.');

                var prev = new JObject(g.Select(o => new JProperty(o.Key, o.Value)));
                foreach (var ns in namespaces.Reverse())
                {
                    var temp = new JObject(new JProperty(ns, prev));
                    prev = temp;
                }

                // 各グループ要素を、全体のJSONオブジェクトにマージ
                root.Merge(prev);
            }

            File.WriteAllText(dstPath, root.ToString());

            return true;
        }