diff --git a/rbac/check_perm.py b/rbac/check_perm.py
index c5dec81..53de9b7 100644
--- a/rbac/check_perm.py
+++ b/rbac/check_perm.py
@@ -84,7 +84,7 @@ async def register_user(sor, ns):
 
 def get_dbname():
 	f = get_serverenv('get_module_dbname')
-	if f i None:
+	if f is None:
 		return None
 	return f('rbac')