def _nested(self, obj, seen, format_callback):
        if seen in obj:
            return []
        seen.add(obj)
        children = []
        for child in self.edges.get(obj, ()):
            children.extend(self._nested(child, seen, format_callback))
        if format_callback:
            ret = [format_callback(obj)]
        else:
            ret = [obj]
        if children:
            ret.append(children)
        return ret
dataset/ETHPy150Open sshwsfc/xadmin/xadmin/util.py/NestedObjects._nested/swapped operands of `in`