code: func (a *AttemptList) Dup() *AttemptList {
  	ret := &AttemptList{}
  	for k, v := range a.To {
  		if ret.To == nil {
  			ret.To = make(map[string]*AttemptList_Nums, len(a.To))
  		}
  		vals := &AttemptList_Nums{Nums: make([]uint32, len(v.Nums))}
  		copy(vals.Nums, v.Nums)
  		ret.To[k] = vals
  	}
  	return ret
  }
docs: // Dup does a deep copy of this AttemptList.