input: Write a function to create an interactive text-based RPG game in Python that allows the player to move around in an environment and battle monsters. The function should define a Player class, a Room class, a Monster class, and include a main game loop where the player can choose actions like moving between rooms or fighting monsters. If the player's health drops to zero or below, the game should end with a defeat message.
  
  
  class Player(object):
   def __init__(self):
   self.health = 100
   self.location = 'room one'
   self.monsters_killed = 0
  
  class Room(object):
   def __init__(self):
   self.name = ''
   self.description = ''
   self.monsters = []
  
   def add_monster(self, monster):
   self.monsters.append(monster)
  
  class Monster(object):
   def __init__(self):
   self.name = ''
   self.health = 100
  
   def attack(self, player):
   player.health -= 10
  
  def start_game():
   player = Player()
  
   while True:
   print(f'You are in {player.location}.')
   print('Available actions: move, fight')
   response = input('What would you like to do? ').lower()
  
   if response == 'move':
   pass
  
   if response == 'fight':
   pass
  
   if player.health <= 0:
   print ('You have been defeated!')
   break
  
  if __name__ == '__main__':
   start_game()
  
  
  assert start_game() is None
output: 
  def start_game():
      class Player(object):
          def __init__(self):
              self.health = 100
              self.location = 'room one'
              self.monsters_killed = 0
  
      class Room(object):
          def __init__(self, name, description):
              self.name = name
              self.description = description
              self.monsters = []
  
          def add_monster(self, monster):
              self.monsters.append(monster)
  
      class Monster(object):
          def __init__(self, name):
              self.name = name
              self.health = 100
  
          def attack(self, player):
              player.health -= 10
  
      rooms = {
          'room one': Room('room one', 'This is the first room.'),
          'room two': Room('room two', 'This is the second room.'),
          'room three': Room('room three', 'This is the third room.')
      }
  
      rooms['room one'].add_monster(Monster('Goblin'))
      rooms['room two'].add_monster(Monster('Orc'))
  
      player = Player()
  
      while True:
          current_room = rooms[player.location]
          print(f'You are in {player.location}. {current_room.description}')
          print('Available actions: move, fight')
          response = input('What would you like to do? ').lower()
  
          if response == 'move':
              print('Available rooms to move to:')
              for room in rooms:
                  if room != player.location:
                      print(room)
              new_location = input('Where would you like to go? ').lower()
              if new_location in rooms:
                  player.location = new_location
              else:
                  print('Invalid room.')
  
          if response == 'fight':
              if current_room.monsters:
                  monster = current_room.monsters[0]
                  print(f'You are fighting a {monster.name}!')
                  while monster.health > 0 and player.health > 0:
                      monster.attack(player)
                      print(f'{monster.name} attacks you! Your health is now {player.health}.')
                      if player.health <= 0:
                          print('You have been defeated!')
                          return
                      player_attack = input('Press enter to attack the monster.').lower()
                      if player_attack == '':
                          monster.health -= 20
                          print(f'You attack the {monster.name}! Its health is now {monster.health}.')
                  if monster.health <= 0:
                      print(f'You have defeated the {monster.name}!')
                      current_room.monsters.remove(monster)
                      player.monsters_killed += 1
              else:
                  print('There are no monsters in this room.')
  
          if player.health <= 0:
              print('You have been defeated!')
              break
  