def add(self, item):
    'Override to not add some items.'
    if (item in self.process_again_list):
        return
    else:
        return super(ProcessAgainList, self).add(item)
Override to not add some items.
def add(self, item):
    
    if (item in self.process_again_list):
        return
    else:
        return super(ProcessAgainList, self).add(item)