query.py 文件源码

def __getitem__(self, s):
        if isinstance(s, six.integer_types):
            # Single index
            assert s >= 0, 'negative indexes are not supported'
            qs = copy(self)
            qs._limits = (s, 1)
            return six.next(iter(qs))
        else:
            # Slice
            assert s.step in (None, 1), 'step is not supported in slices'
            start = s.start or 0
            stop = s.stop or 2**63 - 1
            assert start >= 0 and stop >= 0, 'negative indexes are not supported'
            assert start <= stop, 'start of slice cannot be smaller than its end'
            qs = copy(self)
            qs._limits = (start, stop - start)
            return qs