code: func (list *LinkedList) Sorta() error {
  	list.key.Lock()
  	defer list.key.Unlock()
  
  	var err error
  	list.first, err = mergeSort(list.first, func(a, b interface{}) (int, error) {
  		castA, ok := a.(string)
  		if !ok {
  			return 0, ErrUnexpectedType
  		}
  		castB, ok := b.(string)
  		if !ok {
  			return 0, ErrUnexpectedType
  		}
  
  		return strings.Compare(castA, castB), nil
  	})
  	list.last = findLast(list.first)
  	return err
  }
docs: // Sorta rearranges the position of string entries in this list so that they
  // are ascending.