from typing import List from sqlalchemy.orm import Mapped, mapped_column, relationship from app.extensions import db class Collection(db.Model): id: Mapped[int] = mapped_column(primary_key=True) name: Mapped[str] = mapped_column(unique=True, nullable=False) tasks: Mapped[List['Task']] = relationship("Task", back_populates="collection") users: Mapped[List['User']] = relationship("User", cascade="all, delete-orphan", back_populates="collection")