模拟Range.py

class Range:
    def __init__(self,stop,start=0):
        self.start=start
        self.stop=stop
    def __iter__(self):
        return self
    def __next__(self):
        if self.start > self.stop-1:
            raise StopIteration
        n=self.start
        self.start+=1
        return n
r=Range(10)
for i in r:
    print(i)