::: fastapi.middleware.cors.CORSMiddleware

It can be imported from `fastapi`:

```python
from fastapi.middleware.cors import CORSMiddleware
```

::: fastapi.middleware.gzip.GZipMiddleware

It can be imported from `fastapi`:

```python
from fastapi.middleware.gzip import GZipMiddleware
```

::: fastapi.middleware.httpsredirect.HTTPSRedirectMiddleware

It can be imported from `fastapi`:

```python

You can use:

* `HTTPException`
* `WebSocketException`

These exceptions can be imported directly from `fastapi`:

```python
from fastapi import HTTPException, WebSocketException
```

::: fastapi.HTTPException

We name it `SessionLocal` to distinguish it from the `Session` we are importing from SQLAlchemy.

We will use `Session` (the one imported from SQLAlchemy) later.

To create the `SessionLocal` class, use the function `sessionmaker`:

```Python hl_lines="11"
{!../../../docs_src/sql_databases/sql_app/database.py!}
```

## Technical Details

The class `BackgroundTasks` comes directly from <a href="https://www.starlette.io/background/" class="external-link" target="_blank">`starlette.background`</a>.

It is imported/included directly into FastAPI so that you can import it from `fastapi` and avoid accidentally importing the alternative `BackgroundTask` (without the `s` at the end) from `starlette.background`.

from pydantic.version import VERSION as P_VERSION
from starlette.datastructures import UploadFile
from typing_extensions import Annotated, Literal, get_args, get_origin

# Reassign variable to make it reexported for mypy
PYDANTIC_VERSION = P_VERSION
PYDANTIC_V2 = PYDANTIC_VERSION.startswith("2.")


sequence_annotation_to_type = {
    Sequence: list,
    List: list,
    list: list,
    Tuple: tuple,