/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.

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**.

    assertEquals(c, navigableSet.higher(b));
    assertEquals(null, navigableSet.higher(c));
  }

  /*
   * TODO(cpovirk): make "too small" and "too large" elements available for better navigation
   * testing. At that point, we may be able to eliminate the "hole" tests, which would mean that
   * ContiguousSet's tests would no longer need to suppress them.
   */
  @CollectionSize.Require(SEVERAL)

</div>

/// info

There are other formats and tools to define and install package dependencies.

///

### Create the **FastAPI** Code { #create-the-fastapi-code }

* Create an `app` directory and enter it.
* Create an empty file `__init__.py`.
* Create a `main.py` file with:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")

And we know that editors can't provide a lot of support (like completion) for `dict`s, because they can't know their keys and value types.

We can do better...

## What makes a dependency { #what-makes-a-dependency }

Up to now you have seen dependencies declared as functions.

    /**
     * Clear all pending operations
     */
    public void clearPendingOperations() {
        pendingOperations.clear();
    }

    /**
     * Calculate channel score for load balancing (higher is better)
     *
     * @return channel score
     */
    public int getScore() {
        int score = 100;

        // Adjust based on state
        if (state == ChannelState.ACTIVE)

    assertEquals(c, navigableSet.higher(b));
    assertEquals(null, navigableSet.higher(c));
  }

  /*
   * TODO(cpovirk): make "too small" and "too large" elements available for better navigation
   * testing. At that point, we may be able to eliminate the "hole" tests, which would mean that
   * ContiguousSet's tests would no longer need to suppress them.
   */
  @CollectionSize.Require(SEVERAL)

   *
   * @throws IllegalArgumentException if the resource is not found
   */
  @CanIgnoreReturnValue // being used to check if a resource exists
  // TODO(cgdecker): maybe add a better way to check if a resource exists
  // e.g. Optional<URL> tryGetResource or boolean resourceExists
  public static URL getResource(String resourceName) {
    ClassLoader loader =
        MoreObjects.firstNonNull(

 *  Fix: Handle null fragments.
 *  Fix: Don’t crash on interceptors that throw `IOException` before a
    connection is attempted.
 *  New: Support [WebDAV][webdav] HTTP methods.
 *  New: Buffer WebSocket frames for better performance.
 *  New: Drop support for `TLS_DHE_DSS_WITH_AES_128_CBC_SHA`, our only remaining
    DSS cipher suite. This is consistent with Firefox and Chrome which have also
    dropped these cipher suite.

    return !disjoint(a, b);
  }

  private static Method extractMethod(Test test) {
    if (test instanceof AbstractTester) {
      AbstractTester<?> tester = (AbstractTester<?>) test;
      return getMethod(tester.getClass(), tester.getTestMethodName());
    } else if (test instanceof TestCase) {
      TestCase testCase = (TestCase) test;
      return getMethod(testCase.getClass(), testCase.getName());

Eso define los metadatos sobre el response principal de una *path operation*.

También puedes declarar responses adicionales con sus modelos, códigos de estado, etc.

Hay un capítulo entero en la documentación sobre ello, puedes leerlo en [Responses Adicionales en OpenAPI](additional-responses.md){.internal-link target=_blank}.

## OpenAPI Extra { #openapi-extra }