def __iadd__(self, other):
        "return merged interval spanning both self and other intervals"
        if self.path is not other.path:
            raise ValueError('incompatible intervals cannot be merged.')
        if other.start < self.start:
            self.start = other.start
        if other.stop > self.stop:
            self.stop = other.stop
        return self # iadd MUST ALWAYS RETURN self!!
dataset/ETHPy150Open cjlee112/pygr/pygr/sequence.py/SeqPath.__iadd__/original