# UndoData

```python
gradio.UndoData(···)
```

### Description

The gr.UndoData class is a subclass of gr.Event data that specifically carries information about the `.undo()` event. When gr.UndoData is added as a type hint to an argument of an event listener method, a gr.UndoData object will automatically be passed as the value of that argument. The attributes of this object contains information about the event that triggered the listener.

### Example Usage

```python
import gradio as gr

def undo(retry_data: gr.UndoData, history: list[gr.MessageDict]):
    history_up_to_retry = history[:retry_data.index]
    return history_up_to_retry

with gr.Blocks() as demo:
    chatbot = gr.Chatbot()
    chatbot.undo(undo, chatbot, chatbot)
demo.launch()
```

### Attributes

| Parameter | Type | Default | Description |
|-----------|------|---------|-------------|
| `target` | `Block \| None` | `` | The component object that triggered the event. Can be used to distinguish multiple components bound to the same listener. |
| `data` | `Any` | `` |  |