@Override
  public @NotNull DataIndexer<Integer, Void, FileContent> getIndexer() {
    return new DataIndexer<>() {
      @Override
      public @NotNull Map<Integer, Void> map(@NotNull FileContent inputData) {
        return TrigramBuilder.getTrigramsAsMap(inputData.getContentAsText());
      }
    };
  }
@Override
  public @NotNull DataIndexer<Integer, Void, FileContent> getIndexer()