Menu/Helper.php
public function setDropdown(ItemInterface $dropDownItem)
    {
        $dropDownItem
            ->setUri('#')
            ->setLinkattribute('class', 'dropdown-toggle')
            ->setLinkattribute('data-toggle', 'dropdown')
            ->setAttribute('class', 'dropdown')
            ->setChildrenAttribute('class', 'dropdown-menu');

        $dropDownItem->setLabel($dropDownItem->getLabel() . '<b class="caret"></b>');
        $dropDownItem->setExtra('safe_label', true);
    }
public function setDropdown(ItemInterface $dropDownItem)
    {
        $dropDownItem
            ->setUri('#')
            ->setLinkattribute('class', 'dropdown-toggle')
            ->setLinkattribute('data-toggle', 'dropdown')
            ->setAttribute('class', 'dropdown')
            ->setChildrenAttribute('class', 'dropdown-menu');

        $dropDownItem->setLabel($dropDownItem->getLabel() . '<b class="caret"></b>');
        $dropDownItem->setExtra('safe_label', true);
    }
Creates a drop down menu item from item.

@param ItemInterface $dropDownItem