docs: @Programmatic
      public Blob toExcel(final List<WorksheetContent> worksheetContents, final String fileName) {
          try {
              final File file = newExcelConverter().appendSheet(worksheetContents);
              return excelFileBlobConverter.toBlob(fileName, file);
          } catch (final IOException ex) {
              throw new ExcelService.Exception(ex);
          }
      }