diff --git a/generate/container.py b/generate/container.py
index d8f3f10..eea606d 100644
--- a/generate/container.py
+++ b/generate/container.py
@@ -40,7 +40,7 @@ def maybe(json: dict, key: str) -> ConfigValue:
 def maybe_or(json: dict, key: str, _or: ConfigValue) -> ConfigValue:
     """Maybe get a value, but return _or if it is None."""
     val = maybe(json, key)
-    if val is None or not isinstance(val, _or):
+    if val is None or not isinstance(val, type(_or)):
         return _or
     return val