code: static Gson createGson() {
      if (gson == null) {
        gson = new GsonBuilder()
            .registerTypeAdapter(CMAField.class, new FieldTypeAdapter())
            .registerTypeAdapter(CMAEntry.class, new EntrySerializer())
            .registerTypeAdapter(CMASnapshot.class, new SnapshotDeserializer())
            .registerTypeAdapter(CMALocale.class, new LocaleSerializer())
            .create();
      }
  
      return gson;
    }
docs: Creates and returns a custom {@code Gson} instance.