This is incredibly helpful while developing and debugging code that interacts with your API.

///

## Documentation

And when you open your browser at <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>, you will see an automatic, interactive, API documentation like:

<img src="/img/tutorial/path-params/image01.png">

/// check

		statusCode: 400,
		cause:      err,
	}
}

func errInvalidScanRangeParameter(err error) *s3Error {
	return &s3Error{
		code:       "InvalidRequestParameter",
		message:    "The value of a parameter in ScanRange element is invalid. Check the service API documentation and try again.",
		statusCode: 400,
		cause:      err,
	}

* `externalDocs`: a `dict` describing external documentation with:
    * `description`: a `str` with a short description for the external docs.
    * `url` (**required**): a `str` with the URL for the external documentation.

### Create metadata for tags

Let's try that in an example with tags for `users` and `items`.

The same way, you can declare any other parameter as normally, and additionally, get the `Request` too.

///

## `Request` documentation

You can read more details about the <a href="https://www.starlette.io/requests/" class="external-link" target="_blank">`Request` object in the official Starlette documentation site</a>.

/// note | "Technical Details"

You could also use `from starlette.requests import Request`.

And those Python files are included/injected in the documentation when generating the site.

### Docs for tests

Most of the tests actually run against the example source files in the documentation.

This helps to make sure that:

* The documentation is up-to-date.
* The documentation examples can be run as is.
* Most of the features are covered by the documentation, ensured by test coverage.

It was one of the first examples of **automatic API documentation**, and this was specifically one of the first ideas that inspired "the search for" **FastAPI**.

/// note

Django REST Framework was created by Tom Christie. The same creator of Starlette and Uvicorn, on which **FastAPI** is based.

///

/// check | "Inspired **FastAPI** to"

Have an automatic API documentation web user interface.

///

                    throw new ExpressionDocumentationException(
                            "Failed to read documentation for expression root: " + root, e);
                } catch (XmlPullParserException e) {
                    throw new ExpressionDocumentationException(
                            "Failed to parse documentation for expression root: " + root, e);
                }
            }
        }

## Documentation Tags - OpenAPI

To add tags to your *path operations*, and group them in the docs UI, read the docs for [Tutorial - Path Operation Configurations - Tags](../tutorial/path-operation-configuration.md#tags){.internal-link target=_blank}.

## Documentation Summary and Description - OpenAPI

   * (see the {@code Network} documentation for more information).
   */
  @Test
  public abstract void nodes_checkReturnedSetMutability();

  /**
   * Verifies that the {@code Set} returned by {@code edges} has the expected mutability property
   * (see the {@code Network} documentation for more information).
   */
  @Test

Même s'ils se trouvent dans des modules différents (fichiers Python).

///

## Exclusion d'OpenAPI

Pour exclure un *chemin* du schéma OpenAPI généré (et donc des systèmes de documentation automatiques), utilisez le paramètre `include_in_schema` et assignez-lui la valeur `False` :

```Python hl_lines="6"
{!../../docs_src/path_operation_advanced_configuration/tutorial003.py!}
```