from itertools import cycle, islice
 
class CycleView:
    def __init__(self, seq):
        self.seq = seq
 
    def __getitem__(self, index):
        if isinstance(index, slice):
            start = (index.start or 0) % len(self.seq)
            if (stop := index.stop) is not None:
                stop = start + stop - (index.start or 0)
            return islice(cycle(self.seq), start, stop)
        return self.seq[index % len(self.seq)]
 
DEADVUL = 'x', 'y', 'z'
print(*CycleView(DEADVUL)[:10])
print(*CycleView(DEADVUL)[2000000000:2000000010])

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