def get_child_index(self, key):
        try:
            return self.get_child_keys().index(key)
        except __HOLE__:
            errorstring = ("Can't find key %s in ParentNode %s\n" +
                           "ParentNode items: %s")
            raise TreeWidgetError(errorstring % (key, self.get_key(), 
                                  str(self.get_child_keys())))
dataset/ETHPy150Open AnyMesh/anyMesh-Python/example/urwid/treetools.py/ParentNode.get_child_index