# get_function_first_arg_dict_keys

> **Function** in `langchain_core`

📖 [View in docs](https://reference.langchain.com/python/langchain-core/runnables/utils/get_function_first_arg_dict_keys)

Get the keys of the first argument of a function if it is a dict.

## Signature

```python
get_function_first_arg_dict_keys(
    func: Callable,
) -> list[str] | None
```

## Parameters

| Name | Type | Required | Description |
|------|------|----------|-------------|
| `func` | `Callable` | Yes | The function to check. |

## Returns

`list[str] | None`

The keys of the first argument if it is a dict, None otherwise.

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[View source on GitHub](https://github.com/langchain-ai/langchain/blob/ee95ad6907f5eab94644183393a20aa2a032bb19/libs/core/langchain_core/runnables/utils.py#L365)