code: func dedupInt64s(nums []int64) []int64 {
  	seen := make(map[int64]struct{}, len(nums))
  	res := make([]int64, 0, len(nums))
  	for _, x := range nums {
  		if _, ok := seen[x]; !ok {
  			seen[x] = struct{}{}
  			res = append(res, x)
  		}
  	}
  	return res
  }
docs: // dedupInt64s dedups int64s.