def _on_tree_item_expanded(self, event):

        # Which item was expanded?
        wxid = event.GetItem()

        # The item data is a tuple.  The first element indicates whether or not
        # we have already populated the item with its children.  The second
        # element is the actual item data.
        populated, element = self.control.GetPyData(wxid)

        # Make sure that the element's 'open' icon is displayed etc.
        self._refresh_element(wxid, element)

        # Trait notification.
        self.element_expanded = element

        return
Remove the first item with the passed value from the
dataset/ETHPy150Open enthought/pyface/pyface/viewer/tree_viewer.py/TreeViewer._on_tree_item_expanded--crossover with--dataset/ETHPy150Open armet/python-armet/armet/http/response.py/Headers.remove