Could you explain what the Pydantic library is and what it is used for?

Pydantic is a Python library for data validation and settings management using type annotations. It allows you to create model classes that automatically validate and convert input data into the desired types, ensuring safety and ease of working with data.

Main features of Pydantic:

• Validation of input data when creating objects.
• Automatic type conversion (e.g., string to date).
• Support for nested models.
• Generation of data schemas (e.g., JSON Schema).

Example usage:

from pydantic import BaseModel, ValidationError
from datetime import datetime

class User(BaseModel):
    id: int
    name: str
    signup_ts: datetime = None

try:
    user = User(id='123', name='Alice', signup_ts='2023-01-01T12:00:00')
    print(user)
except ValidationError as e:
    print(e)

Here, Pydantic automatically converts the string '123' to int and the date string to a datetime object, and provides detailed messages in case of errors.