**FastAPI** is helemaal gebaseerd op deze type hints, ze geven veel voordelen.

Maar zelfs als je **FastAPI** nooit gebruikt, heb je er baat bij om er iets over te leren.

/// note

Als je een Python expert bent en alles al weet over type hints, sla dan dit hoofdstuk over.

///

## Motivatie

Laten we beginnen met een eenvoudig voorbeeld:

	cpSrcPath := r.Header.Get(xhttp.AmzCopySource)
	var vid string
	if u, err := url.Parse(cpSrcPath); err == nil {
		vid = strings.TrimSpace(u.Query().Get(xhttp.VersionID))
		// Note that url.Parse does the unescaping
		cpSrcPath = u.Path
	}

	srcBucket, srcObject := path2BucketObject(cpSrcPath)
	// If source object is empty or bucket is empty, reply back invalid copy source.

	return nil
}

// Maximum running concurrent saves on server.
var maxConcurrentScannerSaves = make(chan struct{}, 4)

// save the content of the cache to minioMetaBackgroundOpsBucket with the provided name.
// Note that no locking is done when saving.
func (d *dataUsageCache) save(ctx context.Context, store objectIO, name string) error {
	select {
	case <-ctx.Done():
		return ctx.Err()
	case maxConcurrentScannerSaves <- struct{}{}:

	// content for asynchronous deletion.
	//
	// Note: RestoreObject and HealObject requests don't end up replacing the
	// null version and therefore don't require the free-version to track
	// anything
	if fi.VersionID == "" && !fi.IsRestoreObjReq() && !fi.Healing() {
		// Note: Restore object request reuses PutObject/Multipart
		// upload to copy back its data from the remote tier. This

  }

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")
  public void testCompare() {
    for (double x : VALUES) {
      for (double y : VALUES) {
        // note: spec requires only that the sign is the same
        assertWithMessage(x + ", " + y).that(Doubles.compare(x, y)).isEqualTo(Double.compare(x, y));
      }
    }
  }

  public void testContains() {

    }
  }

  // We need to test that our method behaves like the JDK method.
  @SuppressWarnings("InlineMeInliner")
  public void testCompare() {
    for (long x : VALUES) {
      for (long y : VALUES) {
        // note: spec requires only that the sign is the same
        assertWithMessage(x + ", " + y).that(Longs.compare(x, y)).isEqualTo(Long.compare(x, y));
      }
    }
  }

  public void testContains() {

    an HTTP response if one was returned.

## Version 2.4.0-RC1

_2015-05-16_

 *  **New HttpUrl API.** It's like `java.net.URL` but good. Note that
    `Request.Builder.url()` now throws `IllegalArgumentException` on malformed
    URLs. (Previous releases would throw a `MalformedURLException` when calling
    a malformed URL.)

    void clear() {
      value = null;
    }
  }

  private static final class AvlNode<E extends @Nullable Object> {
    /*
     * For "normal" nodes, the type of this field is `E`, not `@Nullable E` (though note that E is a
     * type that can include null, as in a TreeMultiset<@Nullable String>).
     *
     * For the header node, though, this field contains `null`, regardless of the type of the
     * multiset.
     *

            byte[] data = new byte[128];
            // First sign the data
            digest.sign(data, 0, 128, request, response);

            // Verify should work with valid parameters
            // Note: actual verification result depends on proper setup
            digest.verify(data, 0, 128, 0, response);
        }
    }

```

Entonces, declara tus *path operation functions* con `async def` así:

```Python hl_lines="2"
@app.get('/')
async def read_results():
    results = await some_library()
    return results
```

/// note | Nota

Solo puedes usar `await` dentro de funciones creadas con `async def`.

///

---