@Override
  @NonNull
  public ColumnAdapter<Map<Subject, String>, String> dataConverter() {
    return new ColumnAdapter<Map<Subject, String>, String>() {
      @Override
      @NonNull
      public String encode(@NonNull Map<Subject, String> model) {
        if (model == null) return null;
        Type type = new TypeToken<Map<Subject, String>>(){}.getType();
        Gson gson = new Gson();
        return gson.toJson(model, type);
      }

      @Override
      public Map<Subject, String> decode(String model) {
        if (model == null) return null;
        Type type = new TypeToken<Map<Subject, String>>(){}.getType();
        Gson gson = new Gson();
        return gson.fromJson(model, type);
      }
    };
  }