Construct a dataclass from a dict with unexpected keys

dataclass_util.py

from dataclasses import asdict, fields
from typing import Any, Dict


class DataClassBase:
    @classmethod
    def fromdict(cls, d: Dict[str, Any]):
        """Return a dataclass from a dict which may include unexpected keys."""
        class_fields = {f.name for f in fields(cls)}
        return cls(**{k: v for k, v in d.items() if k in class_fields})

    def asdict(self):
        """Return the fields of a dataclass instance as a new dictionary mapping field names to
        field values."""
        return asdict(self)

example.py

from dataclasses import dataclass
from dataclass_util import DataClassBase


@dataclass
class Person(DataClassBase):
  name: str
  age: int


person = Person.fromdict({'name': 'John Doe', 'age': 42, 'address': None})

print(person.asdict())  # {'name': 'John Doe', 'age': 42}