feat: add UserId value object and update ClassifiedAd to use it

domain/__init__.py

@@ -1 +1 @@
-from .marketplace import classified_ad
+from .marketplace import classified_ad as classified_ad

domain/marketplace/__init__.py

@@ -1 +1,2 @@
-from .classified_ad import ClassifiedAd
+from .classified_ad import ClassifiedAd as ClassifiedAd
+from .user_id import UserId as UserId

domain/marketplace/classified_ad.py

@@ -2,11 +2,13 @@ from dataclasses import dataclass
 from decimal import Decimal
 from uuid import UUID
 
+from domain.marketplace.user_id import UserId
+
 
 @dataclass(frozen=True)
 class ClassifiedAd:
     id: UUID
-    _ownerId: UUID
+    _ownerId: UserId
     title: str
     text: str
-    _price: Decimal
+    _price: Decimal

domain/marketplace/user_id.py

@@ -0,0 +1,7 @@
+from dataclasses import dataclass
+from uuid import UUID
+
+
+@dataclass(frozen=True)
+class UserId:
+    value: UUID