public List <ExtendedTreeNode> Find(IStatement statement, ExtendedTreeNode parent)
        {
            var child = Children.OfType <StatementNode>().FirstOrDefault(rn => rn.Statement == statement);

            return(child != null
                                ? new List <ExtendedTreeNode> {
                parent, this, child
            }
                                : new List <ExtendedTreeNode>());
        }
        public List <ExtendedTreeNode> Find(IConcept concept, ExtendedTreeNode parent)
        {
            var child = Children.OfType <ConceptNode>().FirstOrDefault(c => c.Concept == concept);

            return(child != null
                                ? new List <ExtendedTreeNode> {
                parent, this, child
            }
                                : new List <ExtendedTreeNode>());
        }