'NoneType' object is not iterable
Traceback (most recent call last):
File "lib/draco/dracohandler.py", line 749, in _handler
method(request.pathinfo(), request.args())
File "lib/gazette/phoenix/slide_pub.py", line 984, in slide
self['current_categories'] = issue.slots_meta_order_public()
File "lib/gazette/editorial.py", line 1443, in slots_meta_order_public
for s in self.slots_public():