def __init__(self, start, end):
        assert end is None or 0 >= end, "Bad range end: %r" % end
        self.start = start
        self.end = end # non-inclusive
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/webob-1.2.3/webob/byterange.py/Range.__init__/swapped operands of `>=`