protected void protectSheet( Sheet sheet, String password ) throws KettleException {
    if ( sheet instanceof HSSFSheet ) {
      // Write protect Sheet by setting password
      // works only for xls output at the moment
      sheet.protectSheet( password );
    } else {
      // prevented at UI, but still
      throw new KettleException( "Password protection currently only supported for XLS file format." );
    }
  }
@Test
  public void testProtectSheet() throws Exception {
    step.protectSheet( wb.getSheet( SHEET_NAME ), "aa" );
    assertTrue( wb.getSheet( SHEET_NAME ).getProtect() );
  }