def remove(self, item):
        'Remove first occurence of item.  Raise ValueError if not found'
        i = self.index(item)
        del self._keys[i]
        del self._items[i]
def remove ( self , item ) : i = self . index ( item ) del self . _keys [ i ] del self . _items [ i ]
Remove first occurence of item.  Raise ValueError if not found