* Validation for most (or all?) Python **data types**, including:
    * JSON objects (`dict`).
    * JSON array (`list`) defining item types.
    * String (`str`) fields, defining min and max lengths.
    * Numbers (`int`, `float`) with min and max values, etc.

* Validation for more exotic types, like:
    * URL.
    * Email.
    * UUID.
    * ...and others.

Wystarczy, że napiszesz standardowe deklaracje typów Pythona:

```Python
from datetime import date

from pydantic import BaseModel

# Zadeklaruj parametr jako str
# i uzyskaj wsparcie edytora wewnątrz funkcji
def main(user_id: str):
    return user_id


# Model Pydantic
class User(BaseModel):
    id: int
    name: str
    joined: date
```

A one będą mogły zostać później użyte w następujący sposób:

```Python

```Python
from typing import List, Dict
from datetime import date

from pydantic import BaseModel

# Değişkeni str olarak belirt
# ve o fonksiyon için harika bir editör desteği al
def main(user_id: str):
    return user_id


# Pydantic modeli
class User(BaseModel):
    id: int
    name: str
    joined: date
```

Sonrasında bu şekilde kullanabilirsin

```Python

import pytest
from dirty_equals import IsDict
from fastapi.testclient import TestClient


@pytest.fixture(name="client")
def get_client():
    from docs_src.bigger_applications.app_an.main import app

    client = TestClient(app)
    return client


def test_users_token_jessica(client: TestClient):
    response = client.get("/users?token=jessica")
    assert response.status_code == 200

tolerations: [] affinity: {} # Command to run after the main command on exit exitCommand: "" ## Use this field to add environment variables relevant to MinIO server. These fields will be passed on to MinIO container(s) ## when Chart is deployed environment: ## Please refer for comprehensive list https://docs.min.io/minio/baremetal/reference/minio-server/minio-server.html ## MINIO_SUBNET_LICENSE: "License key obtained from https://subnet.min.io" ## MINIO_BROWSER: "off" ## The name of a secret in the...

     * User controlled relocations.
     * This property is a comma separated list of entries with the syntax <code>GAV&gt;GAV</code>.
     * The first <code>GAV</code> can contain <code>*</code> for any elem (so <code>*:*:*</code> would mean ALL, something
     * you don't want). The second <code>GAV</code> is either fully specified, or also can contain <code>*</code>,
     * then it behaves as "ordinary relocation": the coordinate is preserved from relocated artifact.

	totalRx := int64(0)
	connectTime := time.Now()
	for {
		n, err := io.CopyN(xioutil.Discard, r.Body, 128*humanize.KiByte)
		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
			// would mean the network is not stable. Logging here will help in debugging network issues.
			if time.Since(connectTime) < (globalNetPerfMinDuration - time.Second) {
				adminLogIf(ctx, err)
			}
		}
		totalRx += n

👆 ✍ 🐩 🐍 ⏮️ 🆎:

```Python
from datetime import date

from pydantic import BaseModel

# Declare a variable as a str
# and get editor support inside the function
def main(user_id: str):
    return user_id


# A Pydantic model
class User(BaseModel):
    id: int
    name: str
    joined: date
```

👈 💪 ⤴️ ⚙️ 💖:

```Python

```Python hl_lines="16-18  21-22  28-32"
{!../../docs_src/openapi_callbacks/tutorial001.py!}
```

There are 2 main differences from a normal *path operation*:

* It doesn't need to have any actual code, because your app will never call this code. It's only used to document the *external API*. So, the function could just have `pass`.

```

////

//// tab | Python 3.8+

```Python hl_lines="20"
{!> ../../docs_src/body_nested_models/tutorial004.py!}
```

////

This would mean that **FastAPI** would expect a body similar to:

```JSON
{
    "name": "Foo",
    "description": "The pretender",
    "price": 42.0,
    "tax": 3.2,
    "tags": ["rock", "metal", "bar"],