diff --git a/openstack_auth/backend.py b/openstack_auth/backend.py
index c630fb0a..111e8123 100644
--- a/openstack_auth/backend.py
+++ b/openstack_auth/backend.py
@@ -223,8 +223,8 @@ class KeystoneBackend(object):
             return set()
         # TODO(gabrielhurley): Integrate policy-driven RBAC
         #                      when supported by Keystone.
-        role_perms = set(["openstack.roles.%s" % role['name'].lower()
-                          for role in user.roles])
+        role_perms = {"openstack.roles.%s" % role['name'].lower()
+                      for role in user.roles}
 
         services = []
         for service in user.service_catalog:
@@ -236,8 +236,8 @@ class KeystoneBackend(object):
                                in service.get('endpoints', [])]
             if user.services_region in service_regions:
                 services.append(service_type.lower())
-        service_perms = set(["openstack.services.%s" % service
-                             for service in services])
+        service_perms = {"openstack.services.%s" % service
+                         for service in services}
         return role_perms | service_perms
 
     def has_perm(self, user, perm, obj=None):
diff --git a/openstack_auth/user.py b/openstack_auth/user.py
index fa30fe68..46138822 100644
--- a/openstack_auth/user.py
+++ b/openstack_auth/user.py
@@ -298,12 +298,12 @@ class User(models.AbstractBaseUser, models.AnonymousUser):
 
         Returns ``True`` or ``False``.
         """
-        admin_roles = [role.lower() for role in getattr(
+        admin_roles = {role.lower() for role in getattr(
             settings,
             'OPENSTACK_KEYSTONE_ADMIN_ROLES',
-            ['admin'])]
-        user_roles = [role['name'].lower() for role in self.roles]
-        return True if set(admin_roles).intersection(user_roles) else False
+            ['admin'])}
+        user_roles = {role['name'].lower() for role in self.roles}
+        return not admin_roles.isdisjoint(user_roles)
 
     @property
     def authorized_tenants(self):