import org.jetbrains.annotations.NotNull; class Node { String getType() { return ""; } String foo(Node left, Node right) { String leftType = newMethod(left.getType()); String rightType = newMethod(right.getType()); String type = newMethod("A"); return leftType + rightType + type; } @NotNull private String newMethod(String type2) { return type2.substring(1); } }