def murmer(x, s):
    """
    Compute the Murmer hash of the *k*-mer `x` with the seed `s`,
    returning least significant 61 bits.

    Although *k* is not a parameter, *k*-mers longer than 30bp are
    not guaranteed to produce correct results.
    """

    def _rot64(a, b):
        return a << b | a >> 64 - b

    def _fmix64(k):
        k ^= k >> 33
        k = k * 18397679294719823053 & 18446744073709551615
        k ^= k >> 33
        k = k * 14181476777654086739 & 18446744073709551615
        k ^= k >> 33
        return k
    c1 = 9782798678568883157
    c2 = 5545529020109919103
    h = s
    k = x
    k = k * c1 & 18446744073709551615
    k = (k << 31 | k >> 33) & 18446744073709551615
    k = k * c2 & 18446744073709551615
    h ^= k
    h = (h << 27 | h >> 37) & 18446744073709551615
    h = h * 5 + 1390208809 & 18446744073709551615
    h ^= h >> 33
    h = h * 18397679294719823053 & 18446744073709551615
    h ^= h >> 33
    h = h * 14181476777654086739 & 18446744073709551615
    h ^= h >> 33
    return h
