{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (or `str | None = None` in Python 3.10) has a default of `None`.
* `tax: float = 10.5` has a default of `10.5`.
* `tags: List[str] = []` has a default of an empty list: `[]`.

but you might want to omit them from the result if they were not actually stored.

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (ou `str | None = None` no Python 3.10) tem um padrão de `None`.
* `tax: float = 10.5` tem um padrão de `10.5`.
* `tags: List[str] = []` tem um padrão de uma lista vazia: `[]`.

mas você pode querer omiti-los do resultado se eles não foram realmente armazenados.

## 📨 🏷 🔢 🔢

👆 📨 🏷 💪 ✔️ 🔢 💲, 💖:

{* ../../docs_src/response_model/tutorial004.py hl[11,13:14] *}

* `description: Union[str, None] = None` (⚖️ `str | None = None` 🐍 3️⃣.1️⃣0️⃣) ✔️ 🔢 `None`.
* `tax: float = 10.5` ✔️ 🔢 `10.5`.
* `tags: List[str] = []` 🔢 🛁 📇: `[]`.

✋️ 👆 💪 💚 🚫 👫 ⚪️➡️ 🏁 🚥 👫 🚫 🤙 🏪.

🖼, 🚥 👆 ✔️ 🏷 ⏮️ 📚 📦 🔢 ☁ 💽, ✋️ 👆 🚫 💚 📨 📶 📏 🎻 📨 🌕 🔢 💲.

      assertEquals(
          new Sink(4).putUnencodedChars(s).hash(), new Sink(4).putString(s, UTF_16LE).hash());
    }
  }

  public void testFloat() {
    Sink sink = new Sink(4);
    sink.putFloat(Float.intBitsToFloat(0x04030201));
    HashCode unused = sink.hash();
    sink.assertInvariants(4);
    sink.assertBytes(new byte[] {1, 2, 3, 4});
  }

  public void testDouble() {
    Sink sink = new Sink(8);

# Introductie tot Python Types

Python biedt ondersteuning voor optionele "type hints" (ook wel "type annotaties" genoemd).

Deze **"type hints"** of annotaties zijn een speciale syntax waarmee het <abbr title="bijvoorbeeld: str, int, float, bool">type</abbr> van een variabele kan worden gedeclareerd.

Door types voor je variabelen te declareren, kunnen editors en hulpmiddelen je beter ondersteunen.

```Python hl_lines="4  9 10 11 12  25 26 27"
from typing import Union

from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: Union[bool, None] = None


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):

        if (read(this.tmp, 0, 8) < 0) {
            throw new SmbEndOfFileException();
        }
        return Encdec.dec_uint64be(this.tmp, 0);
    }

    @Override
    public final float readFloat() throws SmbException {
        if (read(this.tmp, 0, 4) < 0) {
            throw new SmbEndOfFileException();
        }
        return Encdec.dec_floatbe(this.tmp, 0);
    }

    @Override

Die Funktionsparameter werden wie folgt erkannt:

* Wenn der Parameter auch im **Pfad** deklariert wurde, wird er als Pfad-Parameter interpretiert.
* Wenn der Parameter ein **einfacher Typ** ist (wie `int`, `float`, `str`, `bool`, usw.), wird er als **Query**-Parameter interpretiert.
* Wenn der Parameter vom Typ eines **Pydantic-Modells** ist, wird er als Request**body** interpretiert.

/// note | Hinweis

{* ../../docs_src/response_model/tutorial004_py310.py hl[9,11:12] *}

* `description: Union[str, None] = None` (o `str | None = None` en Python 3.10) tiene un valor por defecto de `None`.
* `tax: float = 10.5` tiene un valor por defecto de `10.5`.
* `tags: List[str] = []` tiene un valor por defecto de una lista vacía: `[]`.

pero podrías querer omitirlos del resultado si no fueron en realidad almacenados.

```Python hl_lines="2  7 8 9 10  23 24 25"
from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: bool = None


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


@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = None):