diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
index 5f8f76e5b2..c4d11b9637 100644
--- a/scripts/qapi/common.py
+++ b/scripts/qapi/common.py
@@ -205,7 +205,8 @@ def gen_ifcond(ifcond: Optional[Union[str, Dict[str, Any]]],
                cond_fmt: str, not_fmt: str,
                all_operator: str, any_operator: str) -> str:
 
-    def do_gen(ifcond: Union[str, Dict[str, Any]], need_parens: bool):
+    def do_gen(ifcond: Union[str, Dict[str, Any]],
+               need_parens: bool) -> str:
         if isinstance(ifcond, str):
             return cond_fmt % ifcond
         assert isinstance(ifcond, dict) and len(ifcond) == 1