def getsetnx(*args)
      val = args.pop
      keys = args.flatten
      StorageFile.getsetnx(path, [*@parents, *keys], val)
    end
def getsetnx(*args)
      val = args.pop
      keys = args.flatten
      StorageFile.getsetnx(path, [*@parents, *keys], val)
    end
getsetnx(val)
 getsetnx(key, val)
 getsetnx(key1, key2, val)
 getsetnx([key], val)
 getsetnx([key1, key2], val)