What are the best practices for validation in Python?

What are the best practices for validation in Python?

Some best practices include using built-in validation libraries, writing custom validators, and ensuring clear error messages.

Can you give me an example of using a validation library?

Sure! You can use the pydantic library to validate data models easily. For example:

from pydantic import BaseModel, ValidationError

class User(BaseModel):
    name: str
    age: int

try:
    user = User(name='Alice', age='twenty')  # This will raise a validation error
except ValidationError as e:
    print(e)

What about custom validation functions?

You can create custom validation functions by defining a function that checks your conditions and raises exceptions if they fail. For example:

def validate_age(age):
    if age < 0:
        raise ValueError('Age must be a positive integer')

How do I handle validation errors gracefully?

You can handle validation errors by using try-except blocks and providing user-friendly messages. Always log the errors for debugging.