dataclasses_rule.py

""" Arjan asked: which do you prefer, TypedDict or dataclass?  My response: why choose when you can have both? """

from collections.abc import Mapping
from dataclasses import dataclass
from functools import cached_property


@dataclass
class Options(Mapping):
    option1: str = "hello"
    option2: int = 42

    @cached_property
    def fields(self) -> dict:
        return {f.name: getattr(self, f.name) for f in dataclasses.fields(self)}

    def __getitem__(self, key):
        return self.fields[key]

    def __iter__(self):
        return iter(self.fields)

    def __len__(self):
        return len(self.fields)

o = Options(option1="Arjan")
assert list(o.keys())==['option1', 'option2']
assert o['option2'] == 42
opt1, opt2 = o.values()
assert opt1 == "Arjan"