SELECT fieldX, fieldY, fieldZ FROM ...

class TrackingDict(dict):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self._accessed_keys = set()

    def __getitem__(self, key):
        self._accessed_keys.add(key)
        return super().__getitem__(key)

    @property
    def accessed_keys(self):
        return self._accessed_keys

    @property
    def never_accessed_keys(self):
        return set(self.keys()) - self._accessed_keys

user = {
    "name": "John Doe",
    "age": 30,
    "email": "[email protected]",
}
user = TrackingDict(user)

assert user["name"] == "John Doe"

print("Использованные ключи:", user.accessed_keys)
print("Неиспользованные ключи:", user.never_accessed_keys)

Использованные ключи: {'name'}
Неиспользованные ключи: {'email', 'age'}

assert not user.never_accessed_keys, f"Вы не проверили {user.never_accessed_keys}"

from typing import TypeVar, Any

K = TypeVar('K')
V = TypeVar('V')

class TrackingDict(dict[K, V]):
    """
    Словарь с отслеживанием использованных ключей.
    """

    def __init__(self, *args: Any, **kwargs: Any) -> None:
        super().__init__(*args, **kwargs)
        self._accessed_keys: set[K] = set()

    def __getitem__(self, key: K) -> V:
        self._accessed_keys.add(key)
        return super().__getitem__(key)

    @property
    def accessed_keys(self) -> set[K]:
        return self._accessed_keys

    @property
    def never_accessed_keys(self) -> set[K]:
        return set(self.keys()) - self._accessed_keys

def update_dict(d, key, value):
    d[key] = value
    return d

my_dict = {'a': 1, 'b': 2}
print(update_dict(my_dict, 'c', 3))
print(update_dict(my_dict, 'd', 4))
print(my_dict)

def update_dict(d, key, value):
    new_dict = d.copy()
    new_dict[key] = value
    return new_dict