Dataclasses

@dataclass auto-generates __init__, __repr__, and __eq__ from your annotated fields. Modern Python's answer to "a class that just holds data."

Two things to remember

• Use field(default_factory=list) for mutable defaults (never = []!).
• Add frozen=True to make instances immutable (hashable, dict-key safe).

Versus namedtuple / dict

• More readable than dicts (you get attributes, not string lookups)
• More flexible than namedtuple (mutable by default, supports inheritance)
• Less ceremony than a hand-written class

Try it

1. Make Task frozen and put one in a set.
2. Add a due: datetime | None = None field.