/// info | Technical Details

**FastAPI** will know that it can use the class `OAuth2PasswordBearer` (declared in a dependency) to define the security scheme in OpenAPI because it inherits from `fastapi.security.oauth2.OAuth2`, which in turn inherits from `fastapi.security.base.SecurityBase`.

All the security utilities that integrate with OpenAPI (and the automatic API docs) inherit from `SecurityBase`, that's how **FastAPI** can know how to integrate them in OpenAPI.

      }
    }
  }

  private fun ensureAllTaskQueuesIdle() {
    val entryTime = System.nanoTime()

    for (queue in TaskRunner.INSTANCE.activeQueues()) {
      // We wait at most 1 second, so we don't ever turn multiple lost threads into
      // a test timeout failure.
      val waitTime = (entryTime + 1_000_000_000L - System.nanoTime())
      if (!queue.idleLatch().await(waitTime, TimeUnit.NANOSECONDS)) {

You can define arbitrarily deeply nested models:

{* ../../docs_src/body_nested_models/tutorial007_py310.py hl[7,12,18,21,25] *}

/// info

Notice how `Offer` has a list of `Item`s, which in turn have an optional list of `Image`s

///

## Bodies of pure lists { #bodies-of-pure-lists }

Now we are going to update our dependencies.

We want to get the `current_user` *only* if this user is active.

So, we create an additional dependency `get_current_active_user` that in turn uses `get_current_user` as a dependency.

Both of these dependencies will just return an HTTP error if the user doesn't exist, or if is inactive.

* etc.

## Simple and Powerful { #simple-and-powerful }

Although the hierarchical dependency injection system is very simple to define and use, it's still very powerful.

You can define dependencies that in turn can define dependencies themselves.

NetworkPolicy spec](https://kubernetes.io/docs/tasks/administer-cluster/declare-network-policy#before-you-begin),
and set `networkPolicy.enabled` to `true`.

For Kubernetes v1.5 & v1.6, you must also turn on NetworkPolicy by setting
the DefaultDeny namespace annotation. Note: this will enforce policy for *all* pods in the namespace:

```

		ipList.Add(addr)
	}

	return ipList, err
}

// sortIPs - sort ips based on higher octets.
// The logic to sort by last octet is implemented to
// prefer CIDRs with higher octets, this in-turn skips the
// localhost/loopback address to be not preferred as the
// first ip on the list. Subsequently this list helps us print
// a user friendly message with appropriate values.
func sortIPs(ipList []string) []string {

				"X-Amz-Date": now.Format(iso8601Format),
			},
			region:   "",
			expected: ErrUnsignedHeaders,
		},
	}

	// Run each test case individually.
	for i, testCase := range testCases {
		// Turn the map[string]string into map[string][]string, because Go.
		query := url.Values{}
		for key, value := range testCase.queryParams {
			query.Set(key, value)
		}

		// Create a request to use.

doubt that it had a VERY turn-up nose, much more like a snout
than a real nose; also its eyes were getting extremely small for
a baby:  altogether Alice did not like the look of the thing at
all.  `But perhaps it was only sobbing,' she thought, and looked
into its eyes again, to see if there were any tears.

  No, there were no tears.  `If you're going to turn into a pig,

 * [HTTP Public Key Pinning (HPKP)][rfc_7469] or SHA-1 base64 hashes as in Chromium's
 * [static certificates][static_certificates].
 *
 * ## Setting up Certificate Pinning
 *
 * The easiest way to pin a host is turn on pinning with a broken configuration and read the
 * expected configuration when the connection fails. Be sure to do this on a trusted network, and
 * without man-in-the-middle tools like [Charles][charles] or [Fiddler][fiddler].
 *