question: return this node 's key concode_field_sep Node root concode_elem_sep List<Node> children concode_elem_sep char key concode_field_sep void add concode_elem_sep void add concode_elem_sep void add concode_elem_sep List<Node> getChildren concode_elem_sep Node getChild concode_elem_sep Node getRoot concode_elem_sep boolean hasSinglePath concode_elem_sep Node addChild
target: char function ( ) { return key ; }