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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def cmd_repeat(self, args):
        '''repeat a command at regular intervals'''
        if len(args) == 0:
            if len(self.repeats) == 0:
                print("No repeats")
                return
            for i in range(len(self.repeats)):
                print("%u: %s" % (i, self.repeats[i]))
            return
        if args[0] == 'add':
            if len(args) < 3:
                print("Usage: repeat add PERIOD CMD")
                return
            self.repeats.append(RepeatCommand(float(args[1]), " ".join(args[2:])))
        elif args[0] == 'remove':
            if len(args) < 2:
                print("Usage: repeat remove INDEX")
                return
            i = int(args[1])
            if i < 0 or i >= len(self.repeats):
                print("Invalid index %d" % i)
                return
            self.repeats.pop(i)
            return
        elif args[0] == 'clean':
            self.repeats = []
        else:
            print("Usage: repeat <add|remove|clean>")