diff --git a/armi/reactor/blueprints/__init__.py b/armi/reactor/blueprints/__init__.py
index 59a575746..ef35ae187 100644
--- a/armi/reactor/blueprints/__init__.py
+++ b/armi/reactor/blueprints/__init__.py
@@ -154,7 +154,7 @@ def __new__(mcs, name, bases, attrs):
         else:
             pluginSections = pm.hook.defineBlueprintsSections()
             for plug in pluginSections:
-                for attrName, section, resolver in plug:
+                for (attrName, section, resolver) in plug:
                     assert isinstance(section, yamlize.Attribute)
                     if attrName in attrs:
                         raise plugins.PluginError(