I passed but I'm still a bit confused on why. The default code said to "write code" in the Building class but I never did because everything already seemed attached to the Building class (after writing code for School class). I've also never seen class method written outside the class code block. My assumption is that if you create a method but add the class name in the signature it will still attach to the class. I'm having trouble finding anything on this though so I'm not sure if I'm missing something. 
public class Solution {
    public static void main(String[] args) {
        Building school = getSchool();
        Building shop = getBuilding();

        System.out.println(school);
        System.out.println(shop);
    }

    public static Building getSchool() {
        //write your code here
        School sch = new School();
        return sch;
    }

    public static Building getBuilding() {
        //write your code here
        Building build = new Building();
        return build;
    }

    static class School /*write your code here*/ extends Building {
        @Override
        public String toString() {
            return "School";
        }
    }

    static class Building /*write your code here*/ {
        @Override
        public String toString() {
            return "Building";
        }
    }
}