input: def play_game(player1, player2):
      """Implements a rock-paper-scissors game decision-making algorithm.
      Define the winning rules and determine the winner based on player inputs.
      >>> play_game('rock', 'scissors')
      'Player 1 wins!'
      >>> play_game('paper', 'rock')
      'Player 1 wins!'
      >>> play_game('scissors', 'scissors')
      'It is a draw!'
      >>> play_game('scissors', 'paper')
      'Player 1 wins!'
      >>> play_game('rock', 'paper')
      'Player 2 wins!'
      """
      rules = {'rock': 'scissors', 'scissors': 'paper', 'paper': 'rock'}
      if player1 == player2:
          return 'It is a draw!'
      elif rules[player1] == player2:
          return 'Player 1 wins!'
      elif rules[player2] == player1:
          return '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!'
      elif rules[player2] == player1:
          return 'Player 2 wins!'