'Insert the `widget` in a new tab at position `index`.
See also
ToolBox.addItem'

def insertItem(self, index, widget, text, icon=None, toolTip=None):

    button = self.createTabButton(widget, text, icon, toolTip)
    self.__contentsLayout.insertWidget((index * 2), button)
    self.__contentsLayout.insertWidget(((index * 2) + 1), widget)
    widget.hide()
    page = _ToolBoxPage(index, widget, button.defaultAction(), button)
    self.__pages.insert(index, page)
    for i in range((index + 1), self.count()):
        self.__pages[i] = self.__pages[i]._replace(index=i)
    self.__updatePositions()
    if ((self.count() == 1) and (index == 0)):
        page.action.trigger()
    self.__updateSelected()
    self.updateGeometry()
    return index
