docs: public static Map<String, PictureData> getPicMap(Workbook workbook, int sheetIndex) {
  		Assert.notNull(workbook, "Workbook must be not null !");
  		if (sheetIndex < 0) {
  			sheetIndex = 0;
  		}
  
  		if (workbook instanceof HSSFWorkbook) {
  			return getPicMapXls((HSSFWorkbook) workbook, sheetIndex);
  		} else if (workbook instanceof XSSFWorkbook) {
  			return getPicMapXlsx((XSSFWorkbook) workbook, sheetIndex);
  		} else {
  			throw new IllegalArgumentException(StrUtil.format("Workbook type [{}] is not supported!", workbook.getClass()));
  		}
  	}