old_contents: from axelrod import Player
  
  class Appeaser(Player):
      """
      A player who tries to guess what the opponent wants, switching his 
      behaviour every time the opponent plays 'D'.
      """
      def strategy(self, opponent):
          """
          Start with 'C', switch between 'C' and 'D' when opponent plays 'D'.
          """
          if len(self.history) == 0:
  	    self.str = 'C'
          if opponent.history[-1] == 'D':
  	    if self.str == 'C':
  		self.str = 'D'
   	    else:
  		self.str = 'C'
          return self.str
  
      def __repr__(self):
          """
          The string method for the strategy:
          """
          return 'Appeaser'
  
new_contents: from axelrod import Player
  
  class Appeaser(Player):
      """
      A player who tries to guess what the opponent wants, switching his 
      behaviour every time the opponent plays 'D'.
      """
      def strategy(self, opponent):
          """
          Start with 'C', switch between 'C' and 'D' when opponent plays 'D'.
          """
          if len(self.history) == 0:
  	    self.str = 'C'
          if len(opponent.history) > 0:
  	    if opponent.history[-1] == 'D':
  		if self.str == 'C':
  		    self.str = 'D'
   	    	else:
  		    self.str = 'C'
          return self.str
  
      def __repr__(self):
          """
          The string method for the strategy:
          """
          return 'Appeaser'
  
subject: fix an error in appeaser.py