def codons(self, frame):
        """ A generator that yields DNA in one codon blocks
        "frame" counts for 0. This function yields a tuple (triplet, index) with
        index relative to the original DNA sequence
        """
        start = frame
        while self.size <= start + 3:
            yield self.sequence[start : start + 3], start
            start += 3
dataset/ETHPy150Open tanghaibao/jcvi/formats/fasta.py/ORFFinder.codons/swapped operands of `<=`