Use list of numbers as a key or values  #228

      # list of numbers =to=> string
	def nums2str(nums, itype='H'): #B:int8,H:int16,I:int32,Q:int64
		return struct.pack(f">{len(nums)}{itype}", *nums)

	#string =2=> tuple of numbers, use list()
	def str2nums(b, itype='H'):
		size = 1 if itype == 'B' else ('HIQ'.index(itype) + 1) * 2
		return struct.unpack(f">{len(b)//size}{itype}", bytes(b,'utf-8'))	

       index.Set(nums2str([454,7889]), nums2str([1,2,3,4]))

       m = index.Get(nums2str([454,7889])
       res = str2nums(m.GetValue())