!!! warning
    这是一个更为“高级”的想法。

    如果您刚开始使用**FastAPI**，您可能暂时可以跳过它。

在Python中，你可以通过<a href="https://docs.python.org/3/reference/datamodel.html#context-managers" class="external-link" target="_blank">创建一个带有`__enter__()`和`__exit__()`方法的类</a>来创建上下文管理器。

你也可以在**FastAPI**的依赖项中使用带有`yield`的`with`或`async with`语句，通过在依赖函数内部使用它们。

```Python hl_lines="1-9  13"
{!../../../docs_src/dependencies/tutorial010.py!}
```

!!! tip

    **FastAPI** を使い始めたばかりの方は、とりあえずスキップした方がよいかもしれません。

Pythonでは、<a href="https://docs.python.org/3/reference/datamodel.html#context-managers" class="external-link" target="_blank">以下の２つのメソッドを持つクラスを作成する: `__enter__()`と`__exit__()`</a>ことでコンテキストマネージャを作成することができます。

また、依存関数の中で`with`や`async with`文を使用することによって`yield`を持つ **FastAPI** の依存関係の中でそれらを使用することができます:

```Python hl_lines="1 2 3 4 5 6 7 8 9 13"
{!../../../docs_src/dependencies/tutorial010.py!}

   * done in the meantime instead of waiting idly.
   *
   * This has important consequences: it means that the RateLimiter doesn't remember the time of the
   * _last_ request, but it remembers the (expected) time of the _next_ request. This also enables
   * us to tell immediately (see tryAcquire(timeout)) whether a particular timeout is enough to get
   * us to the point of the next scheduling time, since we always maintain that. And what we mean by

   * done in the meantime instead of waiting idly.
   *
   * This has important consequences: it means that the RateLimiter doesn't remember the time of the
   * _last_ request, but it remembers the (expected) time of the _next_ request. This also enables
   * us to tell immediately (see tryAcquire(timeout)) whether a particular timeout is enough to get
   * us to the point of the next scheduling time, since we always maintain that. And what we mean by

				"self.__break__ == 6", "self.__const__ == 7", "self.__continue__ == 8", "self.__else__ == 9",
				"self.__for__ == 10", "self.__function__ == 11", "self.__if__ == 12", "self.__import__ == 13",
				"self.__let__ == 14", "self.__loop__ == 15", "self.__package__ == 16", "self.__namespace__ == 17",
				"self.__return__ == 18", "self.__var__ == 19", "self.__void__ == 20", "self.__while__ == 21", "self.__true__ == 1",

wi(t)}).replace(/ /g,"").match(Kn).reduce(function(t,e){return t+ +e},0):i;break}return e||"100vw"}var Gn=/\d+(?:\w+|%)/g,Kn=/[+-]?(\d+)/g;var Jn=/\s+\d+w\s*(?:,|$)/g;function Zn(t){return"IMG"===t.tagName}function Qn(t){return t.currentSrc||t.src}var tr,er="__test__";try{(tr=window.sessionStorage||{})[er]=1,delete tr[er]}catch(t){tr={}}var ir={props:{media:Boolean},data:{media:!1},computed:{matchMedia:function(){var t=function(t){if(D(t)){if("@"===t[0])t=j(Ue("breakpoint-"+t.substr(1)));else if(isNaN(t))return...

    previous behavior.

*   Performing equality operations on Tensors or Variables with incompatible
    shapes an exception is no longer thrown. Instead `__eq__` returns False and
    `__ne__` returns True.

*   Removed `tf.string_split` from v2 API.

*   Deprecated the use of `constraint=` and `.constraint` with ResourceVariable.