实验楼挑战赛(1)-实现不可修改字典

class ImmutableDict(object):
    def __init__(self, **kwargs):
        self.kwargs = kwargs
    def __getitem__(self,key):
        try:
            return self.kwargs[key]
        except:
            raise TypeError("'ImmutableDict' objects are immutable")
    def pop(self,key):
        raise TypeError("'ImmutableDict' objects are immutable")
    def get(self,key):
        return self.kwargs.get(key)
    def __setitem__(self,key):
　　　　　raise TypeError("'ImmutableDict' objects are immutable")