docs: @Override
      public List<IndexableField> indexableFields(Columns columns) {
  
          Date fromDate = readFrom(columns);
          Date toDate = readTo(columns);
  
          if (fromDate == null && toDate == null) {
              return Collections.emptyList();
          }
  
          validate(fromDate, toDate);
  
          NRShape shape = makeShape(fromDate, toDate);
          return Arrays.asList(strategy.createIndexableFields(shape));
      }