class Person:

    def __init__(self, name):
        self.name = name

    def say_hello(self):
        print("Hello, ", self.name)

p1 = Person("Allan")
p1.say_hello()

p2 = Person("John")
p2.say_hello()

class Classroom:

    def __init__(self):
        self._people = []

    def add_person(self, person):
        self._people.append(person)

    def remove_person(self, person):
        self._people.remove(person)

    def greet(self):
        for person in self._people:
            person.say_hello()

class Person:

    def __init__(self, name):
        self.name = name

    def say_hello(self):
        print("Hello, ", self.name)

room = Classroom()
room.add_person(Person("Scott"))
room.add_person(Person("John"))
room.add_person(Person("Paul"))
room.greet()

Create classroom and some encapsulation