docs: @Nonnull
    public StringComparator naturalStringComparator(final SimpleExtraction simpleExtraction)
    {
      Preconditions.checkNotNull(simpleExtraction, "simpleExtraction");
      if (simpleExtraction.getExtractionFn() != null
          || getColumnType(simpleExtraction.getColumn()) == ValueType.STRING) {
        return StringComparators.LEXICOGRAPHIC;
      } else {
        return StringComparators.NUMERIC;
      }
    }