raw but working version of getting nested users

User model has City model, City model has Country model,
all pydantic models generated by my metaclass

database.py

@@ -48,7 +48,8 @@ def __new__(cls, name, bases, fields):
             field_name for field_name in dir(origin_model)
             if not field_name.startswith('_')
             and field_name not in alchemy_fields
-            and not cls.is_secondary_relation(origin_model, field_name)
+            and not cls.is_property_secondary_relation(origin_model, field_name)
+            and not cls.is_property_foreign_key(origin_model, field_name)
         ]
 
         defined_fields = fields['fields']
@@ -74,9 +75,10 @@ def __new__(cls, name, bases, fields):
         result_fields.update({
             field_name: (fields[field_name], ...)
             for field_name in defined_fields
-            if field_name in origin_model_field_names and
+            if field_name in origin_model_field_names
+            and fields.get(field_name)
             # if alchemy field hasn't 'type' property, it means the field is relation
-            not hasattr(getattr(origin_model, field_name), 'type')
+            and not hasattr(getattr(origin_model, field_name), 'type')
         })
 
         result_model = create_model(
@@ -88,7 +90,7 @@ def __new__(cls, name, bases, fields):
         return result_model
 
     @staticmethod
-    def is_secondary_relation(model, attribute_name):
+    def is_property_secondary_relation(model, attribute_name):
         """Sqlalchemy in its models force define one relation in two models.
         What means. For example will take model order and model product.
         Every order may have one product. In database, in sql when we create
@@ -114,6 +116,19 @@ def is_secondary_relation(model, attribute_name):
         else:
             return False
 
+    @staticmethod
+    def is_property_foreign_key(model, attribute_name):
+        attribute = getattr(model, attribute_name)
+        try:
+            foreign_keys = attribute.foreign_keys
+        except AttributeError:
+            return False
+
+        if foreign_keys:
+            return True
+        else:
+            return False
+
 
 class UserOrm(Base):
     __tablename__ = 'users'

main.py

@@ -63,11 +63,18 @@ class UserCreateModel(UserOrm, metaclass=SqlAlchemyToPydantic):
 @register_route('/users/', ('get', ))
 async def get_users() -> list[UserGetModel]:
     async with db.create_session() as session:
-        sql_query = select(UserOrm)
+        sql_query = select(
+            UserOrm, CityOrm, CountryOrm
+        ).select_from(UserOrm).join(CityOrm).join(CountryOrm)
         result = await session.execute(sql_query)
-        users = result.scalars().all()
-        user_dicts = list(map(get_dict_from_orm_object, users))
-    return json.dumps(user_dicts)
+
+        users = []
+        for user in result.fetchall():
+            user_pydantic = UserGetModel.model_validate(user[0])
+            user_dict = user_pydantic.model_dump()
+            user_dict['birth_date'] = str(user_dict['birth_date'])
+            users.append(user_dict)
+    return json.dumps(users)
 
 
 @register_route('/users/', ('post', ))