input: Write a function that simulates a rock-paper-scissors game between two players. The function should take two inputs, the choices of Player 1 and Player 2, and return the result of the game based on the predefined rules. If both players choose the same option, the game should result in a draw. Otherwise, it should determine the winner based on the standard rock-paper-scissors rules where rock beats scissors, scissors beat paper, and paper beats rock.
  
  def play_game(player1, player2):
      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!'
  
  assert play_game('rock', 'scissors') == 'Player 1 wins!'
  assert play_game('paper', 'rock') == 'Player 1 wins!'
  assert play_game('scissors', 'paper') == 'Player 1 wins!'
  assert play_game('rock', 'rock') == 'It is a draw!'
  assert play_game('paper', 'scissors') == 'Player 2 wins!'
output: def play_game(player1, player2):
      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!'