from typing import Optional from pydantic import BaseModel, Field __all__ = ("NewThingSchema", "ProductInfoSchema") class ProductInfoSchema(BaseModel): price: Optional[str] = None source: Optional[str] = None class NewThingSchema(ProductInfoSchema): id: Optional[int] = Field(default_factory=int) name: str author: str url: Optional[str] = None issue: Optional[int] = None