diff --git a/engine/core/management/commands/demo_data.py b/engine/core/management/commands/demo_data.py
index 9ddccca2..7d7a1f8f 100644
--- a/engine/core/management/commands/demo_data.py
+++ b/engine/core/management/commands/demo_data.py
@@ -99,11 +99,13 @@ class Command(BaseCommand):
     def staff_user(self):
         user, _ = User.objects.get_or_create(
             email=f"staff@{DEMO_EMAIL_DOMAIN}",
-            first_name="Alice",
-            last_name="Schon",
-            is_staff=True,
-            is_active=True,
-            is_verified=True,
+            defaults={
+                "first_name": "Alice",
+                "last_name": "Schon",
+                "is_staff": True,
+                "is_active": True,
+                "is_verified": True,
+            },
         )
         if _:
             user.set_password("Staff!Demo888")
@@ -116,12 +118,14 @@ class Command(BaseCommand):
     def super_user(self):
         user, _ = User.objects.get_or_create(
             email=f"super@{DEMO_EMAIL_DOMAIN}",
-            first_name="Bob",
-            last_name="Schon",
-            is_superuser=True,
-            is_staff=True,
-            is_active=True,
-            is_verified=True,
+            defaults={
+                "first_name": "Bob",
+                "last_name": "Schon",
+                "is_superuser": True,
+                "is_staff": True,
+                "is_active": True,
+                "is_verified": True,
+            },
         )
         if _:
             user.set_password("Super!Demo888")
diff --git a/engine/core/serializers/detail.py b/engine/core/serializers/detail.py
index f656cbb0..e8d978f3 100644
--- a/engine/core/serializers/detail.py
+++ b/engine/core/serializers/detail.py
@@ -107,10 +107,10 @@ class CategoryDetailSerializer(ModelSerializer):
             return list(serializer.data)
         return []
 
-    def get_min_price(self, obj: Category):
+    def get_min_price(self, obj: Category) -> float:
         return obj.min_price
 
-    def get_max_price(self, obj: Category):
+    def get_max_price(self, obj: Category) -> float:
         return obj.max_price