Instead of that, by being an "asynchronous" system, once finished, the task can wait in line a little bit (some microseconds) for the computer / program to finish whatever it went to do, and then come back to take the results and continue working with them.

// to the options or to the current bucket ILM expiry rules.
// Caller should close the channel when done.
// The returned function will return the results once there is enough or input is closed,
// or the context is canceled.
func (o *listPathOptions) gatherResults(ctx context.Context, in <-chan metaCacheEntry) func() (metaCacheEntriesSorted, error) {

```Python
say_hi(name=None)  # This works, None is valid 🎉
```

The good news is, once you are on Python 3.10 you won't have to worry about that, as you will be able to simply use `|` to define unions of types:

{* ../../docs_src/python_types/tutorial009c_py310.py hl[1,4] *}

* The alternative documentation will also reflect the new query parameter and body:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Recap { #recap }

In summary, you declare **once** the types of parameters, body, etc. as function parameters.

You do that with standard modern Python types.

You don't have to learn a new syntax, the methods or classes of a specific library, etc.

		switch {
		case len(features) == 0 || (len(required) > 0 && required[0] < features[0]):
			feature := take(&required)
			if exceptionSet[feature] {
				// An "unfortunate" case: the feature was once
				// included in the API (e.g. go1.txt), but was
				// subsequently removed. These are already
				// acknowledged by being in the file
				// "api/except.txt". No need to print them out
				// here.

 *  Fix: Don't leak a connection when a call is canceled immediately preceding the `onFailure()`
    callback.

 *  Fix: Apply call timeouts when connecting duplex calls, web sockets, and server-sent events.
    Once the streams are established no further timeout is enforced.

 *  Fix: Retain the `Route` when a connection is reused on a redirect or other follow-up. This was

			t.Fatalf("Failed to read header: %s", err)
		}
		if header.Typeflag != TypeReg {
			t.Fatalf("Typeflag should've been %d, found %d", TypeReg, header.Typeflag)
		}
	}
}

// failOnceWriter fails exactly once and then always reports success.
type failOnceWriter bool

func (w *failOnceWriter) Write(b []byte) (int, error) {
	if !*w {
		return 0, io.ErrShortWrite
	}
	*w = true
	return len(b), nil
}

    assertEquals(6, queue.size());
    assertEquals(11, queue.capacity());
    assertEquals(42, queue.maximumSize);
    checkNatural(queue);
  }

  // Now test everything at once

  public void testCreation_allOptions() {
    MinMaxPriorityQueue<Integer> queue =
        MinMaxPriorityQueue.orderedBy(SOME_COMPARATOR)
            .expectedSize(8)
            .maximumSize(42)

        set(Settings.INITIAL_WINDOW_SIZE, OKHTTP_CLIENT_WINDOW_SIZE)
      }
    }

  /**
   * Settings we receive from the peer. Changes to the field are guarded by this. The instance is
   * never mutated once it has been assigned.
   */
  var peerSettings = DEFAULT_SETTINGS

  /** The bytes consumed and acknowledged by the application. */
  val readBytes: WindowCounter = WindowCounter(streamId = 0)

     * builder after this call. This does not change semantics, but may improve performance if
     * {@code expectedValuesPerKey} is a good estimate.
     *
     * <p>This may be called more than once; each newly added key will use the most recent call to
     * {@link #expectedValuesPerKey} as its hint.
     *
     * @throws IllegalArgumentException if {@code expectedValuesPerKey} is negative
     * @since 33.3.0