Data Validation and Serialization with Pydantic

Define Pydantic `BaseModel` schemas for request validation, comparing them to DRF serializers.

Apply fine-grained validation using Pydantic field types, constraints, and the `Field()` function.

Create nested Pydantic models to represent complex, hierarchical JSON structures.

Implement custom validation logic with `@field_validator` and `@model_validator`, comparing them to DRF's `validate_<field>` and `validate` methods.

Use separate Pydantic schemas for create, update, and response representations of a single resource.

Configure Pydantic model behavior, such as ORM integration, using `model_config`.