# FuturesDict

> **Class** in `langgraph`

📖 [View in docs](https://reference.langchain.com/python/langgraph/pregel/_runner/FuturesDict)

## Signature

```python
FuturesDict(
    self,
    event: E,
    callback: weakref.ref[Callable[[PregelExecutableTask, BaseException | None], None]],
    future_type: type[F],
)
```

## Extends

- `Generic[F, E]`
- `dict[F, PregelExecutableTask | None]`

## Constructors

```python
__init__(
    self,
    event: E,
    callback: weakref.ref[Callable[[PregelExecutableTask, BaseException | None], None]],
    future_type: type[F],
) -> None
```

| Name | Type |
|------|------|
| `event` | `E` |
| `callback` | `weakref.ref[Callable[[PregelExecutableTask, BaseException \| None], None]]` |
| `future_type` | `type[F]` |


## Properties

- `event`
- `callback`
- `counter`
- `done`
- `lock`

## Methods

- [`on_done()`](https://reference.langchain.com/python/langgraph/pregel/_runner/FuturesDict/on_done)

---

[View source on GitHub](https://github.com/langchain-ai/langgraph/blob/d27d4b2d9895a4aa83170b4aaa135878f99c7fd6/libs/langgraph/langgraph/pregel/_runner.py#L71)