Now, for FastAPI, it will see the return type and make sure that what you return includes **only** the fields that are declared in the type.

FastAPI does several things internally with Pydantic to make sure that those same rules of class inheritance are not used for the returned data filtering, otherwise you could end up returning much more data than what you expected.

This means that now, if you set a value in a context variable before `yield`, the value would still be available after `yield` (as you would intuitively expect). And it also means that you can reset the context variable with a token afterwards.

For example, this works correctly now:

```Python
from contextvars import ContextVar
from typing import Any, Dict, Optional

## To `async` or not to `async`

As dependencies will also be called by **FastAPI** (the same as your *path operation functions*), the same rules apply while defining your functions.

You can use `async def` or normal `def`.

### Don't worry about style

* Don't worry too much about things like commit message styles, I will squash and merge customizing the commit manually.

* Also don't worry about style rules, there are already automatized tools checking that.

And if there's any other style or consistency need, I'll ask directly for that, or I'll add commits on top with the needed changes.

### Check the code

    # Serialization rules for simple scenarios
    style: Optional[str] = None
    explode: Optional[bool] = None
    allowReserved: Optional[bool] = None
    schema_: Optional[Union[Schema, Reference]] = Field(default=None, alias="schema")
    example: Optional[Any] = None
    examples: Optional[Dict[str, Union[Example, Reference]]] = None
    # Serialization rules for more complex scenarios

```Python
# db._state = PeeweeConnectionState()
```

& 📁 `sql_app/main.py` 📁, 🏤 💪 `async` 🔗 `reset_db_state()` & ❎ ⚫️ ⏮️ `pass`:

```Python
async def reset_db_state():
#     database.db._state._state.set(db_state_default.copy())
#     database.db._state.reset()
    pass
```

⤴️ 🏃 👆 📱 ⏮️ Uvicorn:

<div class="termy">

```console

---

The main point is, **none** of these are **rules written in stone** that you have to blindly follow. You can use these ideas to **evaluate your own use case** and decide what is the best approach for your system, checking out how to manage the concepts of:

* Security - HTTPS