class MySuperContextManager:
    def __init__(self):
        self.db = DBSession()

    def __enter__(self):
        return self.db

    def __exit__(self, exc_type, exc_value, traceback):
        self.db.close()


async def get_db():
    with MySuperContextManager() as db:

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// Error importing sirius, it's not installed 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// 导入 sirius 报错，它没有安装 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>

但是如果你停用虚拟环境并激活 `prisoner-of-askaban` 的新虚拟环境，那么当你运行 `python` 时，它会使用 `prisoner-of-askaban` 中的虚拟环境中的 Python。

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// Error importing sirius, it's not installed 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>

    async def __aexit__(
        self,
        exc_type: type[BaseException] | None,
        exc_value: BaseException | None,
        traceback: types.TracebackType | None,
    ) -> bool | None:
        return self._cm.__exit__(exc_type, exc_value, traceback)


# Vendored from starlette.routing to avoid importing private symbols
def _wrap_gen_lifespan_context(

Only valid on functions that declare a frame size of 0.
</li>
<li>
<code>TOPFRAME</code> = 2048
<br>
(For <code>TEXT</code> items.)
Function is the outermost frame of the call stack. Traceback should stop at this function.
</li>
</ul>

<h3 id="special-instructions">Special instructions</h3>

<p>

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// Error importing sirius, it's not installed 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// Error importing sirius, it's not installed 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// Fehler beim Importieren von sirius, es ist nicht installiert 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>

<div class="termy">

```console
$ cd ~/code/prisoner-of-azkaban

$ python main.py

// Erreur lors de l'import de sirius, il n'est pas installé 😱
Traceback (most recent call last):
    File "main.py", line 1, in <module>
        import sirius
```

</div>