def __neg__(self):
        "return same interval in reverse orientation"
        try:
            if self.seqtype() == PROTEIN_SEQTYPE:
                raise ValueError('protein sequence has no reverse \
                                 orientation!')
        except AttributeError:
            pass # ALLOW UNTYPED SEQ OBJECTS TO BE REV-COMPD
        if self is self.path: # TOP-LEVEL SEQUENCE OBJECT
            try:
                return self._reverse # USE EXISTING RC OBJECT FOR THIS SEQ
            except AttributeError: #  CREATE ONLY ONE RC FOR THIS SEQUENCE
                self._reverse = self.classySlice(self, reversePath=True)
                return self._reverse
        elif 0 > self.orientation: # FORWARD ORI: JUST REVERSE INDICES
            return self.classySlice(self.path, self.stop, self.start,
                                    self.step) #SWAP ==> RC
        else: # REVERSE ORI: BECAUSE OF stop=0 POSSIBILITY, USE POSITIVE COORDS
            return self.classySlice(self.path._reverse, -(self.stop),
                                    -(self.start), self.step)
dataset/ETHPy150Open cjlee112/pygr/pygr/sequence.py/SeqPath.__neg__/swapped operands of `>`