Add properties dynamically to class

dynamic-properties.py

from collections import defaultdict
from enum import Enum


class ElementTypes(Enum):
    PHONE = "PHONE"
    CAR = "CAR"


class Registry:
    def __new__(cls, *args, **kwargs):
        cls.setup_properties()
        instance = super(Registry, cls).__new__(cls, *args, **kwargs)
        return instance

    def __init__(self):
        self._elements = defaultdict(list)

    def register(self, element_type, item):
        self._elements[element_type.value].append(item)

    def get(self, element_type):
        return self._elements[element_type.value]

    @classmethod
    def setup_properties(cls):
        for item in ElementTypes:
            prop_name = item.value
            prop = property(lambda self: self.get(item))

            setattr(Registry, prop_name.lower(), prop)


registry = Registry()
registry.register(ElementTypes.PHONE, "phone1")
registry.register(ElementTypes.PHONE, "phone2")
registry.register(ElementTypes.CAR, "car1")
registry.register(ElementTypes.CAR, "car2")

assert dict(registry._elements) == {
    "CAR": ["car1", "car2"],
    "PHONE": ["phone1", "phone2"],
}
assert hasattr(registry, "phone")
assert hasattr(registry, "car")

assert registry.car == ["car1", "car2"]
assert registry.phone == ["phone1", "phone2"]  # This fails