You can declare `examples` for a Pydantic model that will be added to the generated JSON Schema.

//// tab | Pydantic v2

{* ../../docs_src/schema_extra_example/tutorial001_py310.py hl[13:24] *}

////

//// tab | Pydantic v1

{* ../../docs_src/schema_extra_example/tutorial001_pv1_py310.py hl[13:23] *}

////

 * equivalent elements are added to it, it is undefined which will come first in the output.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
final class TopKSelector<
    T extends @Nullable Object> {

  /**
   * Returns a {@code TopKSelector} that collects the lowest {@code k} elements added to it,

* You can then further modify the `response` before returning it.

{* ../../docs_src/middleware/tutorial001.py hl[8:9,11,14] *}

/// tip

Keep in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

{* ../../docs_src/path_operation_configuration/tutorial001_py310.py hl[1,15] *}

That status code will be used in the response and will be added to the OpenAPI schema.

/// note | Technical Details

You could also use `from starlette import status`.

**FastAPI** is already being used in production in many applications and systems. And the test coverage is kept at 100%. But its development is still moving quickly.

New features are added frequently, bugs are fixed regularly, and the code is still continuously improving.

So, the prefix in this case is `/items`.

We can also add a list of `tags` and extra `responses` that will be applied to all the *path operations* included in this router.

And we can add a list of `dependencies` that will be added to all the *path operations* in the router and will be executed/solved for each request made to them.

/// tip

And as the `Response` can be used frequently to set headers and cookies, **FastAPI** also provides it at `fastapi.Response`.

///

## Custom Headers { #custom-headers }

Keep in mind that custom proprietary headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

        // Try to add suppressed exception
        Exception suppressed = new IllegalArgumentException("Should not be added");
        exception.addSuppressed(suppressed);

        // Suppressed exceptions should not be added when suppression is disabled
        Throwable[] suppressedExceptions = exception.getSuppressed();
        assertEquals(0, suppressedExceptions.length);
    }

## Import Path { #import-path }

First, import `Path` from `fastapi`, and import `Annotated`:

{* ../../docs_src/path_params_numeric_validations/tutorial001_an_py310.py hl[1,3] *}

/// info

FastAPI added support for `Annotated` (and started recommending it) in version 0.95.0.

If you have an older version, you would get errors when trying to use `Annotated`.

In that case, you can disable this feature in **FastAPI**, with the parameter `separate_input_output_schemas=False`.

/// info

Support for `separate_input_output_schemas` was added in FastAPI `0.102.0`. 🤓

///

{* ../../docs_src/separate_openapi_schemas/tutorial002_py310.py hl[10] *}

### Same Schema for Input and Output Models in Docs { #same-schema-for-input-and-output-models-in-docs }