a) Create Classroom class which contains attributes class_name, class_type, class_size
b) Create add_classroom() method to SchoolSystem class which makes an instance of our new Classroom class (make an object), and saves that object into a new classroom_dictionary (same thing we’ve been doing for our previous add_something() methods).
c) Create list_classrooms() method to SchoolSystem class which prints all attributes of all Classroom objects in our classroom_dictionary (same as previous list_something() methods).