* Некоторые из этих "потоков" подходят для реализации аутентификации через сторонний сервис использующий OAuth 2.0 (например, Google, Facebook, Twitter, GitHub и т.д.):
        * `implicit`
        * `clientCredentials`
        * `authorizationCode`
    * Но есть один конкретный "поток", который может быть идеально использован для обработки аутентификации непосредственно в том же приложении:

So, even with the code above that doesn't use Pydantic explicitly, FastAPI is using Pydantic to convert those standard dataclasses to Pydantic's own flavor of dataclasses.

And of course, it supports the same:

* data validation
* data serialization
* data documentation, etc.

## Concepts

- If an object is under legal hold, it cannot be deleted unless the legal hold is explicitly removed for the respective version id. DeleteObjectVersion() would fail otherwise.

   * IllegalArgumentException}.
   */
  public void testBadArguments_badchars() {
    String msg =
        "Alphanumeric characters are always 'safe' " + "and should not be explicitly specified";
    IllegalArgumentException expected =
        assertThrows(IllegalArgumentException.class, () -> new PercentEscaper("-+#abc.!", false));
    assertThat(expected).hasMessageThat().isEqualTo(msg);
  }

    return (Set<V>) super.replaceValues(key, values);
  }

  /**
   * {@inheritDoc}
   *
   * <p>Though the method signature doesn't say so explicitly, the returned map has {@link Set}
   * values.
   */
  @Override
  public Map<K, Collection<V>> asMap() {
    return super.asMap();
  }

  /**
   * Stores a key-value pair in the multimap.
   *

/**
 * The concrete route used by a connection to reach an abstract origin server. When creating a
 * connection the client has many options:
 *
 *  * **HTTP proxy:** a proxy server may be explicitly configured for the client. Otherwise, the
 *    [proxy selector][java.net.ProxySelector] is used. It may return multiple proxies to attempt.

 * }</pre>
 *
 * <p>Note that testing {@link Object#equals(Object)} is more simply done using the {@link
 * EqualsTester}. It includes an extra test against an instance of an arbitrary class without having
 * to explicitly add another equivalence group.
 *
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class EquivalenceTester<T> {
  private static final int REPETITIONS = 3;

 * }</pre>
 *
 * <p>Note that testing {@link Object#equals(Object)} is more simply done using the {@link
 * EqualsTester}. It includes an extra test against an instance of an arbitrary class without having
 * to explicitly add another equivalence group.
 *
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class EquivalenceTester<T> {
  private static final int REPETITIONS = 3;

    "tax": 10.5,
    "tags": []
}
```

FastAPI is smart enough (actually, Pydantic is smart enough) to realize that, even though `description`, `tax`, and `tags` have the same values as the defaults, they were set explicitly (instead of taken from the defaults).

So, they will be included in the JSON response.

/// tip

Notice that the default values can be anything, not only `None`.

The most common is the implicit flow.

The most secure is the code flow, but it's more complex to implement as it requires more steps. As it is more complex, many providers end up suggesting the implicit flow.

/// note

It's common that each authentication provider names their flows in a different way, to make it part of their brand.