## Extra JSON Schema data in Pydantic models { #extra-json-schema-data-in-pydantic-models }

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

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

That extra info will be added as-is to the output **JSON Schema** for that model, and it will be used in the API docs.

For the remaining programs,
we define a new GODEBUG setting that
allows individual programs to opt back in to the old behavior.
A GODEBUG setting may not be added if doing so is infeasible,
but that should be extremely rare.

GODEBUG settings added for compatibility will be maintained
for a minimum of two years (four Go releases).
Some, such as `http2client` and `http2server`,
will be maintained much longer, even indefinitely.

                "Method com.example.Task.getFailOnError(): Is not annotated with @since 2.0. Reason for accepting this: Upgraded property" to listOf("Method added to public class", "Abstract method has been added to this class"),

                It will be added to the generated OpenAPI (e.g. visible at `/docs`).
                """
            ),
        ] = None,
        deprecated: Annotated[
            Optional[bool],
            Doc(
                """
                Mark this *path operation* as deprecated.

                It will be added to the generated OpenAPI (e.g. visible at `/docs`).

        if (changeTypes.contains(METHOD_NEW_DEFAULT) && isKotlinBooleanSourceCompatibilityMethod(jApiMethod, currentAccessors)) {
            // Accept also default `getIsX` methods added to interface that are added for Kotlin source compatibility
            return true;
        }

        if (changeTypes.contains(METHOD_REMOVED)) {

                It will be added to the generated OpenAPI (e.g. visible at `/docs`).
                """
            ),
        ] = None,
        deprecated: Annotated[
            Optional[bool],
            Doc(
                """
                Mark this *path operation* as deprecated.

                It will be added to the generated OpenAPI (e.g. visible at `/docs`).

	Metrics bool   `msg:"m"`
	NoOp    bool   `msg:"np"`
}

// DiskInfo is an extended type which returns current
// disk usage per path.
// The above means that any added/deleted fields are incompatible.
//
// The above means that any added/deleted fields are incompatible.
//
//msgp:tuple DiskInfo
type DiskInfo struct {
	Total      uint64
	Free       uint64
	Used       uint64
	UsedInodes uint64
	FreeInodes uint64

    *   Added `TensorSpec` support for CompositeTensors.
    *   Added `tf.linalg.tridiagonal_solve` op.
    *   Added partial_pivoting input parameter to `tf.linalg.tridiagonal_solve`.
    *   Added gradient to `tf.linalg.tridiagonal_solve`.
    *   Added `tf.linalg.tridiagonal_mul op`.
    *   Added GPU implementation of `tf.linalg.tridiagonal_matmul`.
    *   Added `LinearOperatorToeplitz`.

def test_read_items():
    # Before the lifespan starts, "items" is still empty
    assert items == {}

    with TestClient(app) as client:
        # Inside the "with TestClient" block, the lifespan starts and items added
        assert items == {"foo": {"name": "Fighters"}, "bar": {"name": "Tenders"}}

        response = client.get("/items/foo")
        assert response.status_code == 200
        assert response.json() == {"name": "Fighters"}

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

{* ../../docs_src/middleware/tutorial001_py39.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>.