'Insert category description into \'registry\' list'

def _insert_category(self, desc):

    priority = desc.priority
    priorities = [c.priority for (c, _) in self.registry]
    insertion_i = bisect.bisect_right(priorities, priority)
    item = (desc, [])
    self.registry.insert(insertion_i, item)
    self._categories_dict[desc.name] = item
