input: Write a function to develop an interactive text-based RPG game in Python that gives the player options to move around in an environment and battle monsters. The game should include a Player class, a Room class, and a Monster class. The Player class should have attributes for health, location, and monsters_killed. The Room class should have attributes for name, description, and a list of monsters. The Monster class should have attributes for name and health, and a method to attack the player. The function should start the game and include a main game loop where the player can choose actions like moving to a new room or fighting a monster. If the player's health drops to zero, the game should end with a message indicating the player has been defeated.
  assert develop_game() == None # The function should start the game and return None.
output: def develop_game():
      class Player:
          def __init__(self, health, location):
              self.health = health
              self.location = location
              self.monsters_killed = 0
  
      class Room:
          def __init__(self, name, description, monsters):
              self.name = name
              self.description = description
              self.monsters = monsters
  
      class Monster:
          def __init__(self, name, health):
              self.name = name
              self.health = health
  
          def attack(self, player):
              player.health -= 10
              print(f"{self.name} attacks! Player health is now {player.health}")
  
      def create_rooms():
          return [
              Room("Forest", "A dense forest with tall trees.", [Monster("Wolf", 20), Monster("Bear", 30)]),
              Room("Cave", "A dark and damp cave.", [Monster("Goblin", 15)]),
              Room("Mountain", "A high mountain with a view.", [])
          ]
  
      def display_options(room):
          print(f"You are in the {room.name}. {room.description}")
          if room.monsters:
              print("Monsters in this room:")
              for i, monster in enumerate(room.monsters):
                  print(f"{i + 1}. {monster.name}")
          print("Options:")
          print("1. Move to a new room")
          if room.monsters:
              print("2. Fight a monster")
          print("3. Quit game")
  
      def move_to_new_room(rooms, player):
          print("Choose a room to move to:")
          for i, room in enumerate(rooms):
              print(f"{i + 1}. {room.name}")
          choice = int(input()) - 1
          if 0 <= choice < len(rooms):
              player.location = rooms[choice]
          else:
              print("Invalid choice.")
  
      def fight_monster(room, player):
          print("Choose a monster to fight:")
          for i, monster in enumerate(room.monsters):
              print(f"{i + 1}. {monster.name}")
          choice = int(input()) - 1
          if 0 <= choice < len(room.monsters):
              monster = room.monsters[choice]
              while monster.health > 0 and player.health > 0:
                  monster.attack(player)
                  if player.health <= 0:
                      print("You have been defeated!")
                      return True
                  monster.health -= 10
                  print(f"You attack {monster.name}! Monster health is now {monster.health}")
              if monster.health <= 0:
                  print(f"You defeated the {monster.name}!")
                  player.monsters_killed += 1
                  room.monsters.pop(choice)
          else:
              print("Invalid choice.")
          return False
  
      player = Player(100, None)
      rooms = create_rooms()
      player.location = rooms[0]
  
      while True:
          display_options(player.location)
          choice = input("What do you want to do? ")
          if choice == "1":
              move_to_new_room(rooms, player)
          elif choice == "2" and player.location.monsters:
              if fight_monster(player.location, player):
                  break
          elif choice == "3":
              print("Quitting game.")
              break
          else:
              print("Invalid choice.")
          if player.health <= 0:
              print("You have been defeated!")
              break