<gh_stars>0
def distance(strand_a, strand_b):
    if len(strand_a) != len(strand_b):
        raise ValueError("Strand lengths not equal")

    return sum(x != y for x, y in zip(strand_a, strand_b))

def distance(strand_a, strand_b):
    if len(strand_a) != len(strand_b):
        raise ValueError("Strand lengths not equal")

    return sum(x != y for x, y in zip(strand_a, strand_b))