# get_delta_channels_from_all_channels

> **Function** in `langgraph`

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

DeltaChannels to snapshot on the first update_state of a fresh thread:
the ones it wrote, as the rest have no version and nothing to store.

## Signature

```python
get_delta_channels_from_all_channels(
    channels: Mapping[str, BaseChannel],
    channel_versions: ChannelVersions,
) -> set[str]
```

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[View source on GitHub](https://github.com/langchain-ai/langgraph/blob/2d942085e214ef6b99b6f54ed4d544a7c7c5ac56/libs/langgraph/langgraph/pregel/_checkpoint.py#L100)