中介者模式

def solve():
    class ChatRoom:
        def show_message(____):
            return f'____'
    class User:
        def __init__(____):
            self.name = name
            self.chat_room = None
        def send(____):
            return self.chat_room.show_message(____)
    room = ChatRoom()
    alice = User(____)
    alice.chat_room = room
    print(alice.send(____))