code: @Override
      public XlsWorksheet getSheet(String name)
      {
          XlsWorksheet ret = null;
          if(workbook != null)
          {
              Sheet sheet = workbook.getSheet(name);
              if(sheet != null)
                  ret = new XlsWorksheet(sheet);
          }
          else if(writableWorkbook != null)
          {
              Sheet sheet = writableWorkbook.getSheet(name);
              if(sheet != null)
                  ret = new XlsWorksheet(sheet);
          }
          return ret;
      }
docs: Returns the worksheet with the given name in the workbook.
  @param name The name of the worksheet
  @return The worksheet with the given name in the workbook