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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!}
```

### Create a `Base` class

Now we will use the function `declarative_base()` that returns a class.

And you can declare dependencies with `async def` inside of normal `def` *path operation functions*, or `def` dependencies inside of `async def` *path operation functions*, etc.

It doesn't matter. **FastAPI** will know what to do.

!!! note
    If you don't know, check the [Async: *"In a hurry?"*](../../async.md#in-a-hurry){.internal-link target=_blank} section about `async` and `await` in the docs.

```

1. This is the generator function. It's a "generator function" because it contains `yield` statements inside.
2. By using a `with` block, we make sure that the file-like object is closed after the generator function is done. So, after it finishes sending the response.
3. This `yield from` tells the function to iterate over that thing named `file_like`. And then, for each part iterated, yield that part as coming from this generator function.