diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index 0b66d80842..225a82e20d 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -239,11 +239,11 @@ def check_flags(expr: _JSONObject, info: QAPISourceInfo) -> None:
         When certain flags have an invalid value, or when
         incompatible flags are present.
     """
-    for key in ['gen', 'success-response']:
+    for key in ('gen', 'success-response'):
         if key in expr and expr[key] is not False:
             raise QAPISemError(
                 info, "flag '%s' may only use false value" % key)
-    for key in ['boxed', 'allow-oob', 'allow-preconfig', 'coroutine']:
+    for key in ('boxed', 'allow-oob', 'allow-preconfig', 'coroutine'):
         if key in expr and expr[key] is not True:
             raise QAPISemError(
                 info, "flag '%s' may only use true value" % key)