```Python
= None
```

or the:

```Python
= Query(default=None)
```

as it will use that `None` as the default value, and that way make the parameter **not required**.

The `Union[str, None]` part allows your editor to provide better support, but it is not what tells FastAPI that this parameter is not required.

///

 * href="https://en.wikipedia.org/wiki/Graph_(discrete_mathematics)">graph</a>-structured data.
 *
 * <p>This interface is meant to be used as the type of a parameter to graph algorithms (such as
 * topological sort) that only need a way of accessing the predecessors of a node in a graph.
 *
 * <h3>Usage</h3>
 *
 * Given an algorithm, for example:
 *
 * <pre>{@code

 *   <li>NullAway, which will <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treat it
 *       identically to {@code Nullable} as of version 0.9.9</a>. To treat it that way before then,
 *       you can set {@code
 *       -XepOpt:NullAway:CustomNullableAnnotations=com.google.common.base.ParametricNullness,...,com.google.common.util.concurrent.ParametricNullness},

 *   <li>NullAway, which will <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treat it
 *       identically to {@code Nullable} as of version 0.9.9</a>. To treat it that way before then,
 *       you can set {@code
 *       -XepOpt:NullAway:CustomNullableAnnotations=com.google.common.base.ParametricNullness,...,com.google.common.util.concurrent.ParametricNullness},

        logger.debug(indent + artifact + " (not setting artifactScope to: " + ignoredScope + "; local artifactScope "
                + artifact.getScope() + " wins)");

        // TODO better way than static? this might hide messages in a reactor
        if (!ignoredArtifacts.contains(artifact)) {
            logger.warn("\n\tArtifact " + artifact + " retains local artifactScope '" + artifact.getScope()

In these cases, it could make sense to store the tags in an `Enum`.

**FastAPI** supports that the same way as with plain strings:

```Python hl_lines="1  8-10  13  18"
{!../../docs_src/path_operation_configuration/tutorial002b.py!}
```

## Summary and description

You can add a `summary` and `description`:

BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
DAMAGE.

com.esotericsoftware.kryo:kryo
com.esotericsoftware.minlog:minlog
Copyright (c) 2008-2018, Nathan Sweet All rights reserved.

 *   <li>NullAway, which will <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treat it
 *       identically to {@code Nullable} as of version 0.9.9</a>. To treat it that way before then,
 *       you can set {@code
 *       -XepOpt:NullAway:CustomNullableAnnotations=com.google.common.base.ParametricNullness,...,com.google.common.util.concurrent.ParametricNullness},

 *   <li>NullAway, which will <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treat it
 *       identically to {@code Nullable} as of version 0.9.9</a>. To treat it that way before then,
 *       you can set {@code
 *       -XepOpt:NullAway:CustomNullableAnnotations=com.google.common.base.ParametricNullness,...,com.google.common.util.concurrent.ParametricNullness},

 *   <li>NullAway, which will <a
 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treat it
 *       identically to {@code Nullable} as of version 0.9.9</a>. To treat it that way before then,
 *       you can set {@code
 *       -XepOpt:NullAway:CustomNullableAnnotations=com.google.common.base.ParametricNullness,...,com.google.common.util.concurrent.ParametricNullness},