code: def takeDependency(self, item):
          
          if ( not item in self._dependencies ):
              return
          
          item._reverseDependencies.pop(self)
          viewItem = self._dependencies.pop(item)
          
          scene    = viewItem.scene()
          if ( scene ):
              scene.removeItem(viewItem)
docs: Removes the dependency between the this item and the inputed target.
          
          :param      item | <XGanttWidgetItem>