```Python hl_lines="4  11  15-18"
{!../../../docs_src/templates/tutorial001.py!}
```

!!! note
    Before FastAPI 0.108.0, Starlette 0.29.0, the `name` was the first parameter.

    Also, before that, in previous versions, the `request` object was passed as part of the key-value pairs in the context for Jinja2.

!!! tip

    ```

Se você se comunicar com essa *operação de caminho* enviando dois cabeçalhos HTTP como:

```
X-Token: foo
X-Token: bar
```

A resposta seria como:

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

## Recapitulando

Declare cabeçalhos com `Header`, usando o mesmo padrão comum que utiliza-se em `Query`, `Path` e `Cookie`.

```Python
old_dict = {
    "old key": "old value",
    "second old key": "second old value",
}
new_dict = {**old_dict, "new key": "new value"}
```

Here, `new_dict` will contain all the key-value pairs from `old_dict` plus the new key-value pair:

```Python
{
    "old key": "old value",
    "second old key": "second old value",
    "new key": "new value",
}
```

        elif isinstance(item, dict):
            assert len(item) == 1
            values = list(item.values())
            if not values:
                continue
            if isinstance(values[0], str):
                resolve_file(item=values[0], files=files, config=config)
            elif isinstance(values[0], list):
                resolve_files(items=values[0], files=files, config=config)
            else:

* Retrieve the stored data.
* Put that data in a Pydantic model.
* Generate a `dict` without default values from the input model (using `exclude_unset`).
    * This way you can update only the values actually set by the user, instead of overriding values already stored with default values in your model.
* Create a copy of the stored model, updating it's attributes with the received partial updates (using the `update` parameter).

import json
from pathlib import Path

file_path = Path("./openapi.json")
openapi_content = json.loads(file_path.read_text())

for path_data in openapi_content["paths"].values():
    for operation in path_data.values():
        tag = operation["tags"][0]
        operation_id = operation["operationId"]
        to_remove = f"{tag}-"
        new_operation_id = operation_id[len(to_remove) :]
        operation["operationId"] = new_operation_id

from typing import Union

from fastapi import FastAPI, Header

app = FastAPI()


@app.get("/items/")
async def read_items(x_token: Union[list[str], None] = Header(default=None)):

class ModelC(ModelB):
    password: str


class ModelA(BaseModel):
    name: str
    description: Optional[str] = None
    model_b: ModelB

    @validator("name")
    def lower_username(cls, name: str, values):
        if not name.endswith("A"):
            raise ValueError("name must end in A")
        return name


async def get_model_c() -> ModelC:
    return ModelC(username="test-user", password="test-password")

async def read_notes():
    query = notes.select()
    return await database.fetch_all(query)


@app.post("/notes/", response_model=Note)
async def create_note(note: NoteIn):
    query = notes.insert().values(text=note.text, completed=note.completed)
    last_record_id = await database.execute(query)

!!! note
    FastAPI will know that the value of `q` is not required because of the default value `= None`.

    The `Union` in `Union[str, None]` is not used by FastAPI, but will allow your editor to give you better support and detect errors.

## Without Pydantic