This function is a bit hard to type as-is; mypy needs some assertions to
assist with the type narrowing.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 scripts/qapi/schema.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index 775766c0135..66a78f28fd4 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -997,7 +997,9 @@ def lookup_entity(self, name, typ=None):
         return ent
 
     def lookup_type(self, name):
-        return self.lookup_entity(name, QAPISchemaType)
+        typ = self.lookup_entity(name, QAPISchemaType)
+        assert typ is None or isinstance(typ, QAPISchemaType)
+        return typ
 
     def resolve_type(self, name, info, what):
         typ = self.lookup_type(name)
-- 
2.43.0