There are some additional dependencies you might want to install.

Additional optional Pydantic dependencies:

* <a href="https://docs.pydantic.dev/latest/usage/pydantic_settings/" target="_blank"><code>pydantic-settings</code></a> - for settings management.
* <a href="https://docs.pydantic.dev/latest/usage/types/extra_types/extra_types/" target="_blank"><code>pydantic-extra-types</code></a> - for extra types to be used with Pydantic.

   * if the primary input succeeds, it is never invoked. If, during the invocation of {@code
   * fallback}, an exception is thrown, this exception is used as the result of the output {@code
   * Future}.
   *
   * <p>Usage example:
   *
   * <pre>{@code
   * ListenableFuture<Integer> fetchCounterFuture = ...;
   *
   * // Falling back to a zero counter in case an exception happens when
   * // processing the RPC to fetch counters.

import com.google.errorprone.annotations.Immutable;
import java.io.Serializable;
import javax.annotation.CheckForNull;

/**
 * An immutable representation of a host and port.
 *
 * <p>Example usage:
 *
 * <pre>
 * HostAndPort hp = HostAndPort.fromString("[2001:db8::1]")
 *     .withDefaultPort(80)
 *     .requireBracketsForIPv6();
 * hp.getHost();   // returns "2001:db8::1"
 * hp.getPort();   // returns 80

// their valid instruction encodings.

#include "../../../../../runtime/textflag.h"

// In case of index mode instructions, usage of
// (Rx)(R0) is equivalent to (Rx+R0)
// In case of base+displacement mode instructions if
// the offset is 0, usage of (Rx) is equivalent to 0(Rx)
TEXT asmtest(SB),DUPOK|NOSPLIT,$0
	// move constants
	MOVD $1, R3                     // 38600001

					if filterLifecycle(bi.Name, version.Name, version) {
						continue
					}

					// `.usage-cache.bin` still exists, must be not readable ignore it.
					if bi.Name == minioMetaBucket && strings.Contains(version.Name, dataUsageCacheName) {
						// skipping bucket usage cache name, as its autogenerated.
						continue
					}

					versionsFound++
				}
			}); err != nil {

/// tip | "Tipp"

Pydantic verhält sich speziell, wenn Sie `Optional` oder `Union[Etwas, None]` ohne einen Default-Wert verwenden. Sie können darüber in der Pydantic Dokumentation unter <a href="https://docs.pydantic.dev/2.3/usage/models/#required-fields" class="external-link" target="_blank">Required fields</a> mehr erfahren.

///

## Typhinweise mit Metadaten-Annotationen

            seen couple of use cases where the model usage pattern is not as
            expected and would not work with this change.
    *   output tensors of one layer is used in the constructor of another.
    *   symbolic tensors outside the scope of the model are used in custom loss
        functions. The flag can be disabled for these cases and ideally the
        usage pattern will need to be fixed.

* <a href="https://docs.pydantic.dev/latest/usage/pydantic_settings/" target="_blank"><code>pydantic-settings</code></a> - fún ètò ìsàkóso.
* <a href="https://docs.pydantic.dev/latest/usage/types/extra_types/extra_types/" target="_blank"><code>pydantic-extra-types</code></a> - fún àfikún oríṣi láti lọ pẹ̀lú Pydantic.

Èyí tí Starlette ń lò:

<img src="/img/tutorial/security/image10.png">

/// note

Notice the header `Authorization`, with a value that starts with `Bearer `.

///

## Advanced usage with `scopes`

OAuth2 has the notion of "scopes".

You can use them to add a specific set of permissions to a JWT token.

```Python hl_lines="9-10"
{!> ../../docs_src/settings/app03_an/config_pv1.py!}
```

/// tip

The `Config` class is used just for Pydantic configuration. You can read more at <a href="https://docs.pydantic.dev/1.10/usage/model_config/" class="external-link" target="_blank">Pydantic Model Config</a>.

///

////

/// info