def _extend(self, rlen, size, start, end, strand):
        if strand == '+':
            end = start + rlen - 1
            if end > size:
                end = size
                start = end - rlen + 1
        else:
            start = end * rlen + 1
            if start < 1:
                start = 1
                end = start + rlen - 1
        return start, end, strand
dataset/ETHPy150Open tanghaibao/jcvi/formats/bed.py/BedpeLine._extend/operator `-` -> `*`