// You could create an env var MY_NAME with
    $ export MY_NAME="Wade Wilson"

    // Then you could use it with other programs, like
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "🚪 📋"

    <div class="termy">

    ```console
    // Create an env var MY_NAME
    $ $Env:MY_NAME = "Wade Wilson"

    // Use it with other programs, like
    $ echo "Hello $Env:MY_NAME"

<img src="/img/python-types/image06.png">

Notice that this means "`one_person` is an **instance** of the class `Person`".

It doesn't mean "`one_person` is the **class** called `Person`".

## Pydantic models

<a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic</a> is a Python library to perform data validation.

You declare the "shape" of the data as classes with attributes.

| `license_info`...

## Running on Startup

In most cases, when you create a web API, you want it to be **always running**, uninterrupted, so that your clients can always access it. This is of course, unless you have a specific reason why you want it to run only in certain situations, but most of the time you want it constantly running and **available**.

### In a Remote Server

    // You could create an env var MY_NAME with
    $ export MY_NAME="Wade Wilson"

    // Then you could use it with other programs, like
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "Windows PowerShell"

    <div class="termy">

    ```console
    // Create an env var MY_NAME
    $ $Env:MY_NAME = "Wade Wilson"

    // Use it with other programs, like

from .utils import needs_pydanticv1, needs_pydanticv2


class Person:
    def __init__(self, name: str):
        self.name = name


class Pet:
    def __init__(self, owner: Person, name: str):
        self.owner = owner
        self.name = name


@dataclass
class Item:
    name: str
    count: int


class DictablePerson(Person):
    def __iter__(self):

    $ export MY_NAME="Wade Wilson"

    // 然后您可以与其他程序一起使用它，例如
    $ echo "Hello $MY_NAME"

    Hello Wade Wilson
    ```

    </div>

=== "Windows PowerShell"

    <div class="termy">

    ```console
    // 创建一个名为 MY_NAME 的环境变量
    $ $Env:MY_NAME = "Wade Wilson"

    // 与其他程序一起使用它，例如
    $ echo "Hello $Env:MY_NAME"

    Hello Wade Wilson
    ```

    </div>

<img src="/img/python-types/image06.png">

Beachten Sie, das bedeutet: „`one_person` ist eine **Instanz** der Klasse `Person`“.

Es bedeutet nicht: „`one_person` ist die **Klasse** genannt `Person`“.

## Pydantic Modelle

<a href="https://pydantic-docs.helpmanual.io/" class="external-link" target="_blank">Pydantic</a> ist eine Python-Bibliothek für die Validierung von Daten.

<img src="/img/python-types/image06.png">

লক্ষ্য করুন যে এর মানে হল "`one_person` হল ক্লাস `Person`-এর একটি **ইন্সট্যান্স**।"

এর মানে এটি নয় যে "`one_person` হল **ক্লাস** যাকে বলা হয় `Person`।"

## Pydantic মডেল

[Pydantic](https://docs.pydantic.dev/) হল একটি Python লাইব্রেরি যা ডাটা ভ্যালিডেশন সম্পাদন করে।

আপনি ডাটার "আকার" এট্রিবিউট সহ ক্লাস হিসেবে ঘোষণা করেন।

### Tip olarak Sınıflar

Bir değişkenin tipini bir sınıf ile bildirebilirsiniz.

Diyelim ki  `name` değerine sahip `Person` sınıfınız var:

```Python hl_lines="1-3"
{!../../../docs_src/python_types/tutorial010.py!}
```

Sonra bir değişkeni 'Person' tipinde tanımlayabilirsiniz:

```Python hl_lines="6"
{!../../../docs_src/python_types/tutorial010.py!}
```