* Validate **complex structures**:
    * Use of hierarchical Pydantic models, Python `typing`’s `List` and `Dict`, etc.
    * And validators allow complex data schemas to be clearly and easily defined, checked and documented as JSON Schema.
    * You can have deeply **nested JSON** objects and have them all validated and annotated.
* **Extensible**:

    ```

=== "Python 3.8+"

    ```Python hl_lines="4  10"
    {!> ../../../docs_src/body_nested_models/tutorial005.py!}
    ```

The string will be checked to be a valid URL, and documented in JSON Schema / OpenAPI as such.

## Attributes with lists of submodels

You can also use Pydantic models as subtypes of `list`, `set`, etc.:

=== "Python 3.10+"

          required: true
        - label: I already checked if it is not related to FastAPI but to [Pydantic](https://github.com/pydantic/pydantic).
          required: true
        - label: I already checked if it is not related to FastAPI but to [Swagger UI](https://github.com/swagger-api/swagger-ui).
          required: true
        - label: I already checked if it is not related to FastAPI but to [ReDoc](https://github.com/Redocly/redoc).