Не могу понять, что не так

package com.javarush.task.task08.task0824; import java.util.ArrayList; import java.util.Collections; import java.util.List; /* Собираем семейство */ public class Solution { public static void main(String[] args) { //напишите тут ваш код ArrayList<Human> children = new ArrayList<>(); Human ch1 = new Human("Ребенок 1", true, 2); Human ch2 = new Human("Ребенок 2", true, 22); Human ch3 = new Human("Ребенок 3", true, 13); children.add(ch1); children.add(ch2); children.add(ch3); ArrayList<Human> mothers = new ArrayList<>(); ArrayList<Human> fathers = new ArrayList<>(); Human father = new Human("Папа", true, 43, children); Human mother = new Human("Мама", false, 33, children); fathers.add(father); mothers.add(mother); Human gFather1 = new Human("Папа Мамы", true, 76, mothers); Human gMother1 = new Human("Мама Мамы", false, 77, mothers); Human gFather2 = new Human("Папа Папы", true, 67, fathers); Human gMother2 = new Human("Мамы Папы", false, 76, fathers); ArrayList<Human> family = new ArrayList<>(); family.add(ch1); family.add(ch2); family.add(ch3); family.add(father); family.add(mother); family.add(gFather1); family.add(gMother1); family.add(gFather2); family.add(gMother2); System.out.println(family); } public static class Human { //напишите тут ваш код String name; Boolean sex; int age; ArrayList<Human> children = new ArrayList<>(); public Human (String name, Boolean sex, int age, ArrayList<Human> children){ this.name = name; this.sex = sex; this.age = age; this.children = children; } public Human (String name, Boolean sex, int age){ this.name = name; this.sex = sex; this.age = age; } public String toString() { String text = ""; text += "Имя: " + this.name; text += ", пол: " + (this.sex ? "мужской" : "женский"); text += ", возраст: " + this.age; int childCount = this.children.size(); if (childCount > 0) { text += ", дети: " + this.children.get(0).name; for (int i = 1; i < childCount; i++) { Human child = this.children.get(i); text += ", " + child.name; } } return text; } } }