But when you import `Query`, `Path`, `Depends`, `Security` and others from `fastapi`, those are actually functions that return special classes.

///

## Use `SecurityScopes` { #use-securityscopes }

Now update the dependency `get_current_user`.

This is the one used by the dependencies above.

    // at sun.security.pkcs12.PKCS12KeyStore.setKeyEntry
    // http://openjdk.java.net/jeps/229
    // http://hg.openjdk.java.net/jdk9/jdk9/jdk/file/2c1c21d11e58/src/share/classes/sun/security/pkcs12/PKCS12KeyStore.java#l596
    val keystoreType = if (platform.isJdk9()) "JKS" else null
    val x509KeyManager = newKeyManager(keystoreType, heldCertificate, *intermediates)
    val trustManager =

            client_secret=client_secret,
        )


class OAuth2(SecurityBase):
    """
    This is the base class for OAuth2 authentication, an instance of it would be used
    as a dependency. All other OAuth2 classes inherit from it and customize it for
    each OAuth2 flow.

    You normally would not create a new class inheriting from it but use one of the

  public void testGet_bad() {
    ImmutableIntArray iia = ImmutableIntArray.of(0, 1, 3);
    assertThrows(IndexOutOfBoundsException.class, () -> iia.get(-1));
    assertThrows(IndexOutOfBoundsException.class, () -> iia.get(3));

    ImmutableIntArray sub = iia.subArray(1, 2);
    assertThrows(IndexOutOfBoundsException.class, () -> sub.get(-1));
  }

  public void testIndexOf() {

 *
 * <h3>Building a {@code Graph}</h3>
 *
 * <p>The implementation classes that {@code common.graph} provides are not public, by design. To
 * create an instance of one of the built-in implementations of {@code Graph}, use the {@link
 * GraphBuilder} class:
 *
 * {@snippet :
 * MutableGraph<Integer> graph = GraphBuilder.undirected().build();
 * }
 *

        BlockingQueue.class,
        BlockingDeque.class,
        PriorityBlockingQueue.class,
        DelayQueue.class,
        SynchronousQueue.class,
        ConcurrentMap.class,
        ConcurrentNavigableMap.class,
        AtomicReference.class,
        AtomicBoolean.class,
        AtomicInteger.class,
        AtomicLong.class,
        AtomicDouble.class);
  }

 *
 * <h3>Building a {@code ValueGraph}</h3>
 *
 * <p>The implementation classes that {@code common.graph} provides are not public, by design. To
 * create an instance of one of the built-in implementations of {@code ValueGraph}, use the {@link
 * ValueGraphBuilder} class:
 *
 * {@snippet :
 * MutableValueGraph<Integer, Double> graph = ValueGraphBuilder.directed().build();
 * }
 *

  @Override
  @J2ktIncompatible
  @GwtIncompatible
    Object writeReplace() {
    return super.writeReplace();
  }

  // This class is never actually serialized directly, but we have to make the
  // warning go away (and suppressing would suppress for all nested classes too)
  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

 * all elements in priority order and place them in another collection.
 *
 * <p>Operations on this class make no guarantees about the ordering of elements with equal
 * priority. If you need to enforce an ordering, you can define custom classes or comparators that
 * use a secondary key to break ties in primary priority values. For example, here is a class that
 * applies first-in-first-out tie-breaking to comparable elements. To use it, you would insert a

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

////

使用 `str | None` 而不是仅仅 `str`，可以让编辑器帮助你发现把值当成总是 `str` 的错误（实际上它也可能是 `None`）。

### 类作为类型 { #classes-as-types }

你也可以把类声明为变量的类型。

假设你有一个名为 `Person` 的类，带有 name：

{* ../../docs_src/python_types/tutorial010_py310.py hl[1:3] *}

然后你可以声明一个变量是 `Person` 类型：