code: public void setValue(Set<Token[]> tokensSet) {
          if (tokensSet == null) {
              throw new IllegalArgumentException("tokensSet must not be null");
          }
          if (type == null) {
              type = ItemType.SET;
          }
          if (!isListableType()) {
              throw new IllegalArgumentException("The type of this item must be 'set', 'array' or 'list'");
          }
          tokensList = new ArrayList<>(tokensSet);
      }
docs: Sets a value to this Set type item.
  
  @param tokensSet the tokens set