The `--no-cache-dir` option tells `pip` to not save the downloaded packages locally, as that is only if `pip` was going to be run again to install the same packages, but that's not the case when working with containers.

    !!! note
        The `--no-cache-dir` is only related to `pip`, it has nothing to do with Docker or containers.

4. Installiere die Paketabhängigkeiten aus der Anforderungsdatei.

### Criando o Código do **FastAPI**

* Crie um diretório `app` e entre nele.
* Crie um arquivo vazio `__init__.py`.
* Crie um arquivo `main.py` com:

```Python
from typing import Optional

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")