def removeItems(self, tasks):
super(TaskList, self).removeItems(tasks)
for task in self._compositesAndAllChildren(tasks):
for category in task.categories():
category.removeCategorizable(task)
def extend(self, tasks):
super(TaskList, self).extend(tasks)
for task in self._compositesAndAllChildren(tasks):
for category in task.categories():
category.addCategorizable(task)