sem4_3

class Range:
    def __init__(self, start, stop=None, step=1):
        self.step = step
        if stop:
            self.start = start
            self.stop = stop
        else:
            self.start = 0
            self.stop = start
        self.range = range(self.start, self.stop, self.step)

    def __repr__(self):
        if self.step == 1:
            return "Range({}, {})".format(self.start, self.stop)
        else:
            return "Range({}, {}, {})".format(self.start, self.stop, self.step)

    def __contains__(self, o):
        return o in self.range

    def __getitem__(self, item):
        return self.range.__getitem__(item)

    def __len__(self):
        return len(self.range)