Please help!

package com.codegym.task.task08.task0824; import java.util.ArrayList; /* Make a family */ public class Solution { public static void main(String[] args) { //write your code here ArrayList<Human> children = new ArrayList<Human>(); children.add(new Human("Dao", false, 23, new ArrayList<>())); children.add(new Human("Ca", false, 18, new ArrayList<>())); children.add(new Human("Chau", false, 16, new ArrayList<>())); ArrayList<Human> parents = new ArrayList<Human>(); Human dad = new Human("Ba", true, 50, children); Human mom = new Human("Me", false, 48, children); parents.add(dad); parents.add(mom); ArrayList<Human> grandparents1 = new ArrayList<Human>(); grandparents1.add(new Human("Ong noi", true, 80, parents)); grandparents1.add(new Human("Ba noi", false, 78, parents)); ArrayList<Human> grandparents2 = new ArrayList<Human>(); grandparents2.add(new Human("Ong noi", true, 88, parents)); grandparents2.add(new Human("Ba ngoai", true, 79, parents)); ArrayList<Human> family =new ArrayList<Human>(); family.addAll(grandparents1); family.addAll(grandparents2); family.addAll(parents); family.addAll(children); for(Human person : family){ System.out.println(person.toString()); } } public static class Human { //write your code here String name; boolean sex; int age; ArrayList<Human> children; public Human(String name, boolean sex, int age) { this.name = name; this.sex = sex; this.age = age; } public Human(String name, boolean sex, int age, ArrayList<Human> children) { this.name = name; this.sex = sex; this.age = age; this.children = children; } public String toString() { String text = ""; text += "Name: " + this.name; text += ", sex: " + (this.sex ? "male" : "female"); text += ", age: " + this.age; int childCount = this.children.size(); if (childCount > 0) { text += ", children: " + this.children.get(0).name; for (int i = 1; i < childCount; i++) { Human child = this.children.get(i); text += ", " + child.name; } } return text; } } }