code: @Programmatic
      public List<List<?>> fromExcel(
              final Blob excelBlob,
              final List<WorksheetSpec> worksheetSpecs) throws ExcelService.Exception {
          try {
              return newExcelConverter().fromBytes(worksheetSpecs, excelBlob.getBytes());
          } catch (final IOException | InvalidFormatException e) {
              throw new ExcelService.Exception(e);
          }
      }
docs: As {@link #fromExcel(Blob, WorksheetSpec)}, but reading multiple sheets (and returning a list of lists of
  domain objects).