```

////

#### `Union` বা `Optional` ব্যবহার

যদি আপনি Python 3.10-এর নীচের সংস্করণ ব্যবহার করেন, তবে এখানে আমার খুবই **ব্যক্তিগত** দৃষ্টিভঙ্গি থেকে একটি টিপস:

* 🚨 `Optional[SomeType]` ব্যবহার এড়িয়ে চলুন।
* এর পরিবর্তে ✨ **`Union[SomeType, None]` ব্যবহার করুন** ✨।

    * Giá trị của `dict` này là kiểu `float` (đó là giá của mỗi vật phẩm).

#### Union

Bạn có thể khai báo rằng một biến có thể là **một vài kiểu dữ liệu" bất kì, ví dụ, một `int` hoặc một `str`.

Trong Python 3.6 hoặc lớn hơn (bao gồm Python 3.10) bạn có thể sử dụng kiểu `Union` từ `typing` và đặt trong dấu ngoặc vuông những giá trị được chấp nhận.

    this.selfLoopCount = checkNonNegative(selfLoopCount);
    checkState(selfLoopCount <= inEdgeMap.size() && selfLoopCount <= outEdgeMap.size());
  }

  @Override
  public Set<N> adjacentNodes() {
    return Sets.union(predecessors(), successors());
  }

  @Override
  public Set<E> incidentEdges() {
    return new AbstractSet<E>() {
      @Override
      public UnmodifiableIterator<E> iterator() {

{!> ../../docs_src/python_types/tutorial009b.py!}
```

////

#### استفاده از `Union` یا `Optional`

اگه از نسخه پایتون زیر 3.10 استفاده می‌کنی، یه نکته از دید خیلی **شخصی** خودم:

* 🚨 از `Optional[SomeType]` استفاده نکن
* به جاش ✨ **از `Union[SomeType, None]` استفاده کن** ✨.

</div>

## 🖼

### ✍ ⚫️

* ✍ 📁 `main.py` ⏮️:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


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

<details markdown="1">

## דוגמא

### צרו אותה

-   צרו קובץ בשם `main.py` עם:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


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

<details markdown="1">

    Multiset<String> ms2 = HashMultiset.create(asList("a", "b", "b", "c"));
    assertThat(union(ms1, ms2)).containsExactly("a", "a", "b", "b", "c");
  }

  public void testUnionEqualMultisets() {
    Multiset<String> ms1 = HashMultiset.create(asList("a", "b", "a"));
    Multiset<String> ms2 = HashMultiset.create(asList("a", "b", "a"));
    assertEquals(ms1, union(ms1, ms2));
  }

  public void testUnionEmptyNonempty() {

## উদাহরণ

### তৈরি

- `main.py` নামে একটি ফাইল তৈরি করুন:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


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

<details markdown="1">

### Hozd létre

* Hozz létre a `main.py` fájlt a következő tartalommal:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


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

<details markdown="1">

## Ejemplo

### Créalo

* Crea un archivo `main.py` con:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


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


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

<details markdown="1">