[PATCH 08/19] qapi/schema: add static typing and assertions to lookup_type()

[John Snow]

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 | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index a1094283828..3308f334872 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -968,8 +968,12 @@ def lookup_entity(self, name, typ=None):
             return None
         return ent
 
-    def lookup_type(self, name):
-        return self.lookup_entity(name, QAPISchemaType)
+    def lookup_type(self, name: str) -> Optional[QAPISchemaType]:
+        typ = self.lookup_entity(name, QAPISchemaType)
+        if typ is None:
+            return None
+        assert isinstance(typ, QAPISchemaType)
+        return typ
 
     def resolve_type(self, name, info, what):
         typ = self.lookup_type(name)
-- 
2.41.0