diff --git a/bdebstrap b/bdebstrap
index f9a6cc4..04a6fd0 100755
--- a/bdebstrap
+++ b/bdebstrap
@@ -65,7 +65,7 @@ MMDEBSTRAP_OPTS = {
 }
 
 
-class Config(dict):
+class Config(dict[str, typing.Any]):
     """YAML configuration for bdebstrap."""
 
     _ENV_PREFIX = "BDEBSTRAP_"