input: 
  def play_game(player1, player2):
      """ This function simulates a rock-paper-scissors game between two players.
      The rules are defined in a dictionary where 'rock' beats 'scissors',
      'scissors' beats 'paper', and 'paper' beats 'rock'. If both players
      choose the same item, the game is a draw. Else, the player whose
      choice beats the other one wins.
      >>> play_game('rock', 'scissors')
      'Player 1 wins!'
      >>> play_game('paper', 'paper')
      'It is a draw!'
      >>> play_game('scissors', 'rock')
      'Player 2 wins!'
      """
  
output:     rules = {'rock': 'scissors', 'scissors': 'paper', 'paper': 'rock'}
      if player1 == player2:
          return 'It is a draw!'
      elif rules[player1] == player2:
          return 'Player 1 wins!'
      else:
          return 'Player 2 wins!'