undo unexpected change

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(