code: @Override
      protected void doPerform() {
          Select select = getSelectElement();
          if (!select.isMultiple()) {
              throw new UnsupportedOperationException("You may only deselect all options of a multi-select");
          }
  
          for (WebElement option : select.getOptions()) {
              if (!option.isSelected()) {
                  option.click();
              }
          }
      }
docs: /* (non-Javadoc)
  @see com.vilt.minium.actions.DefaultInteraction#doPerform()