# SourcePolicy

> **Class** in `langchain_parallel`

📖 [View in docs](https://reference.langchain.com/python/langchain-parallel/_types/SourcePolicy)

Domain allow/deny lists and freshness floor for web research.

Apex-domain semantics: include `nature.com`, not `https://www.nature.com`.
Wildcards permitted (e.g. `.org`).

## Signature

```python
SourcePolicy()
```

## Extends

- `BaseModel`

## Properties

- `include_domains`
- `exclude_domains`
- `after_date`

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[View source on GitHub](https://github.com/parallel-web/langchain-parallel/blob/c1f8c1d657b86eaf948c363f84fed6ea6bd65754/langchain_parallel/_types.py#L65)