Having `str | None` will allow your editor to give you better support and detect errors.

///

## Additional validation { #additional-validation }

We are going to enforce that even though `q` is optional, whenever it is provided, **its length doesn't exceed 50 characters**.

### Import `Query` and `Annotated` { #import-query-and-annotated }

To achieve that, first import:

* `Query` from `fastapi`
* `Annotated` from `typing`

	},
}

// Set of s3 handler options as bit flags.
type s3HFlag uint8

const (
	// when provided, disables Gzip compression.
	noGZS3HFlag = 1 << iota

	// when provided, enables only tracing of headers. Otherwise, both headers
	// and body are traced.
	traceHdrsS3HFlag

	// when provided, disables throttling via the `maxClients` middleware.
	noThrottleS3HFlag
)

  /**
   * Returns a new {@link ByteSink} for writing bytes to the given file. The given {@code modes}
   * control how the file is opened for writing. When no mode is provided, the file will be
   * truncated before writing. When the {@link FileWriteMode#APPEND APPEND} mode is provided, writes
   * will append to the end of the file without truncating it.
   *
   * @since 14.0
   */

      <version>1.0</version>
      <scope>compile</scope>
    </dependency>

    <dependency>
      <groupId>maven-test</groupId>
      <artifactId>scope-provided</artifactId>
      <version>1.0</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>maven-inherited</groupId>
      <artifactId>scope-default</artifactId>
      <version>1.0</version>
    </dependency>

 * It maintains the state of a Maven execution and provides access to all core services and components.
 * Sessions are thread-safe and can be obtained in session-scoped components using the
 * {@link org.apache.maven.api.di.SessionScoped} annotation.</p>
 *
 * <p>Key capabilities provided through the Session include:</p>
 * <ul>
 *   <li>Access to the current {@link org.apache.maven.api.Project}</li>

        .cache(dnsCache)
        .build()
    dnsProviders =
      providers(
        client = bootstrapClient,
        http2Only = true,
        workingOnly = true,
        getOnly = true,
      )
    runBatch(dnsProviders, names)
    println("cached second run\n*****************\n")
    dnsProviders =
      providers(
        client = bootstrapClient,
        http2Only = true,

```

/// tip

The second argument to <a href="https://docs.python.org/3.8/library/os.html#os.getenv" class="external-link" target="_blank">`os.getenv()`</a> is the default value to return.

If not provided, it's `None` by default, here we provide `"World"` as the default value to use.

///

Then you could call that Python program:

//// tab | Linux, macOS, Windows Bash

<div class="termy">

```console

import org.apache.maven.api.annotations.Nonnull;
import org.apache.maven.api.annotations.Nullable;

/**
 * Interface to manage the project state and artifacts during the Maven build lifecycle.
 * This service provides operations to:
 * <ul>
 *   <li>Manage project artifacts (main and attached)</li>
 *   <li>Handle source roots and resources</li>
 *   <li>Access and modify project properties</li>

  in {{{./apidocs/org/apache/maven/lifecycle/providers/packaging/package-summary.html}<<<org.apache.maven.lifecycle.providers.packaging>>>}} package
  because they are specific for each packaging:

%{toc|fromDepth=2}

  Versions of the plugins are shared in a few constants:

%{snippet|id=versions|file=${project.basedir}/src/main/java/org/apache/maven/lifecycle/providers/packaging/AbstractLifecycleMappingProvider.java}

# Dependencies { #dependencies }

**FastAPI** has a very powerful but intuitive **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection" { #what-is-dependency-injection }