docs: @SuppressWarnings("unchecked")
  	public T setSheet(int sheetIndex) {
  		try {
  			this.sheet = this.workbook.getSheetAt(sheetIndex);
  		} catch (IllegalArgumentException e) {
  			this.sheet = this.workbook.createSheet();
  		}
  		if (null == this.sheet) {
  			this.sheet = this.workbook.createSheet();
  		}
  		return (T) this;
  	}