def _latest_common_snapshot(some, others):
    others_set = set(others)
    for snapshot in reversed(some):
        if snapshot in others_set:
            return snapshot
    return None
Greatest common divisor using Euclid's algorithm.
dataset/ETHPy150Open ClusterHQ/flocker/flocker/volume/filesystems/zfs.py/_latest_common_snapshot--crossover with--dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/test/test_binop.py/gcd