DeprecationWarning: Rail XML format is deprecated

import os
from guardrails import Guard

# BROKEN: Using deprecated Rail XML format (guardrails-ai 0.4.x)
guard = Guard.from_rail_string("""
<rail version="0.1">
  <output>
    <string name="email" description="User email"/>
    <string name="name" description="User name"/>
  </output>
  <validators>
    <validator name="valid_email" on-fail="exception"/>
  </validators>
</rail>
""")

response = guard.validate("user@example.com")
print(response)

import os
from pydantic import BaseModel, EmailStr, field_validator
from guardrails import Guard, register_validator, ValidationError

# FIXED: Using Python-based Guard definition (guardrails-ai 0.5+)
class UserOutput(BaseModel):
    """User data schema."""
    email: EmailStr  # Built-in email validation via Pydantic
    name: str
    
    @field_validator('name')
    @classmethod
    def name_not_empty(cls, v):
        if not v or len(v.strip()) == 0:
            raise ValueError('Name cannot be empty')
        return v

# Create Guard from Pydantic model instead of Rail XML
guard = Guard.from_pydantic(UserOutput)

try:
    response = guard.validate({"email": "user@example.com", "name": "John Doe"})
    print(f"Validation passed: {response.validated_output}")
except ValidationError as e:
    print(f"Validation failed: {e}")