from pydantic import BaseModel from typing import Optional from datetime import datetime class TodoBase(BaseModel): title: str description: Optional[str] = None completed: bool = False class TodoCreate(TodoBase): pass class TodoUpdate(BaseModel): title: Optional[str] = None description: Optional[str] = None completed: Optional[bool] = None class TodoResponse(TodoBase): id: int created_at: datetime updated_at: Optional[datetime] = None class Config: from_attributes = True