input: from typing import Literal, Tuple
  
  def play_game(player1: Literal['rock', 'paper', 'scissors'], player2: Literal['rock', 'paper', 'scissors']) -> str:
      """ Decision-making algorithm for a rock-paper-scissors game.
      >>> play_game('rock', 'scissors')
      'Player 1 wins!'
      >>> play_game('scissors', 'paper')
      'Player 1 wins!'
      >>> play_game('paper', 'rock')
      'Player 1 wins!'
      >>> play_game('rock', 'rock')
      'It is a draw!'
      >>> play_game('scissors', 'rock')
      '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:     else:
          raise ValueError("Invalid input")