code: def OnRemoveCards(self, removedcards):
          
          parentnode = self.root
          for cardtoremove in removedcards:
              (childCard, cookie) = self.GetFirstChild(parentnode)
              while childCard.IsOk():
                  if self.GetItemText(childCard) == \
                          toHexString(cardtoremove.atr):
                      self.Delete(childCard)
                  (childCard, cookie) = self.GetNextChild(parentnode, cookie)
          self.Expand(self.root)
          self.EnsureVisible(self.root)
          self.Repaint()
docs: Called when a card is removed.
          Removes a card from the tree.