<font color="#4E9A06">INFO</font>:     Application startup complete.
```

</div>

That command line program called `fastapi` is **FastAPI CLI**.

FastAPI CLI takes the path to your Python program and automatically detects the variable with the FastAPI (commonly named `app`) and how to import it, and then serves it.

For production you would use `fastapi run` instead. 🚀

                "value": {
                    "name": "Bar",
                    "price": "35.4",
                },
            },
            "invalid": {
                "summary": "Invalid data is rejected with an error",
                "value": {
                    "name": "Baz",
                    "price": "thirty five point four",
                },
            },
        },
    ),
):

                                    },
                                    "invalid": {
                                        "summary": "Invalid data is rejected with an error",
                                        "value": {
                                            "name": "Baz",
                                            "price": "thirty five point four",

                                    },
                                    "invalid": {
                                        "summary": "Invalid data is rejected with an error",
                                        "value": {
                                            "name": "Baz",
                                            "price": "thirty five point four",

INFO:     Application startup complete.
```

</div>

<details markdown="1">
<summary>About the command <code>fastapi dev main.py</code>...</summary>

The command `fastapi dev` reads your `main.py` file, detects the **FastAPI** app in it, and starts a server using <a href="https://www.uvicorn.org" class="external-link" target="_blank">Uvicorn</a>.

By default, `fastapi dev` will start with auto-reload enabled for local development.

        ```python
        from fastapi import FastAPI

        app = FastAPI()

        @app.delete("/items/{item_id}")
        def delete_item(item_id: str):
            return {"message": "Item deleted"}
        ```
        """
        return self.router.delete(
            path,
            response_model=response_model,
            status_code=status_code,
            tags=tags,

```Python hl_lines="1 4"
{!../../../docs_src/python_types/tutorial009.py!}
```

O uso de `Opcional [str]` em vez de apenas `str` permitirá que o editor o ajude a detectar erros, onde você pode estar assumindo que um valor é sempre um `str`, quando na verdade também pode ser `None`.

#### Tipos genéricos

Esses tipos que usam parâmetros de tipo entre colchetes, como:

* `List`

```Python hl_lines="1  4"
{!../../../docs_src/python_types/tutorial009.py!}
```

Utiliser `Optional[str]` plutôt que `str` permettra à l'éditeur de vous aider à détecter les erreurs où vous supposeriez qu'une valeur est toujours de type `str`, alors qu'elle pourrait aussi être `None`.

#### Types génériques

Les types qui peuvent contenir des paramètres de types entre crochets, comme :

                        "name": "Bar",
                        "price": "35.4",
                    },
                },
                "invalid": {
                    "summary": "Invalid data is rejected with an error",
                    "value": {
                        "name": "Baz",
                        "price": "thirty five point four",
                    },
                },
            },
        ),

                "value": {
                    "name": "Bar",
                    "price": "35.4",
                },
            },
            "invalid": {
                "summary": "Invalid data is rejected with an error",
                "value": {
                    "name": "Baz",
                    "price": "thirty five point four",
                },
            },
        },
    ),
):