text: public override ICollection<IParseTree> Evaluate(IParseTree t){IList<IParseTree> nodes = new List<IParseTree>();foreach (ITree c in Trees.GetChildren(t)){if (c is ITerminalNode){ITerminalNode tnode = (ITerminalNode)c;if ((tnode.Symbol.Type == tokenType && !invert) || (tnode.Symbol.Type != tokenType && invert)){nodes.Add(tnode);}}}return nodes;}