diff --git a/api/kiwi_vpn_api/routers/admin.py b/api/kiwi_vpn_api/routers/admin.py
index 14eeacf..758b100 100644
--- a/api/kiwi_vpn_api/routers/admin.py
+++ b/api/kiwi_vpn_api/routers/admin.py
@@ -63,7 +63,7 @@ async def create_initial_admin(
 
     # create an administrative user
     new_user = User.create(**admin_user.dict())
-    new_user.set_capabilities((UserCapabilityType.admin))
+    new_user.set_capabilities([UserCapabilityType.admin])
     new_user.update()
 
 
diff --git a/api/kiwi_vpn_api/routers/user.py b/api/kiwi_vpn_api/routers/user.py
index ad69d26..1db468c 100644
--- a/api/kiwi_vpn_api/routers/user.py
+++ b/api/kiwi_vpn_api/routers/user.py
@@ -88,7 +88,7 @@ async def add_user(
 
     # actually create the new user
     new_user = User.create(**user.dict())
-    new_user.set_capabilities((UserCapabilityType.login))
+    new_user.set_capabilities([UserCapabilityType.login])
 
     # fail if creation was unsuccessful
     if new_user is None:
@@ -149,9 +149,7 @@ async def extend_capabilities(
     # get and change the user
     user = User.get(user_name)
 
-    user.set_capabilities(
-        user.get_capabilities() | set(capabilities)
-    )
+    user.set_capabilities(user.get_capabilities() | set(capabilities))
 
     user.update()
 
@@ -177,8 +175,6 @@ async def remove_capabilities(
     # get and change the user
     user = User.get(user_name)
 
-    user.set_capabilities(
-        user.get_capabilities() - set(capabilities)
-    )
+    user.set_capabilities(user.get_capabilities() - set(capabilities))
 
     user.update()