Returns the gantt widget that this item is linked to.
        
        :return     <XGanttWidget> || None

def ganttWidget(self):
        """
        Returns the gantt widget that this item is linked to.
        
        :return     <XGanttWidget> || None
        """
        tree = self.treeWidget()
        if ( not tree ):
            return None
        
        from projexui.widgets.xganttwidget import XGanttWidget
        return projexui.ancestor(tree, XGanttWidget)