class View(object):
    """docstring for View."""
    __instance = None
    def __init__(self):
        super(View, self).__init__()
        if View.__instance !=None:
            raise Exception('not a thing')
        else:
            View.__instance  = self

    @staticmethod
    def updated(ls):
        print(f'added {list(*ls)}')

    @staticmethod
    def deleted(ls):
        print(f'deleted {list(ls)}')

    @staticmethod
    def displayed(ls):
        print(f'contents {list(ls)}')