Validated Metaclass

validated.py

import typing
import functools

from dataclasses import dataclass


def validated_set(self, value, field_name, field_type):

    if not isinstance(value, field_type):
        raise TypeError(
            f'"{field_name}" should be "{field_type.__name__}". '
            f'Value: {value!r}'
        )

    self.__dict__[field_name] = value


class Validated(type):

    def __init__(cls, name, bases, attrs, **kwargs):
        for field_name, field_type in cls.__annotations__.items():
            fset = functools.partial(
                validated_set,
                field_name=field_name,
                field_type=field_type
            )
            validated_property = property(
                fset=fset
            )
            setattr(cls, field_name, validated_property)


@dataclass
class Employee(metaclass=Validated):
    name: str
    id: int