new_contents: global round_num
  first_or_not = 0
  
  def tit_for_tat(my_history, opponent_history):
      global round_num
      global first_or_not
      p = 0
      
      if round_num == None and first_or_not == 1:
          first_or_not = 1
          
      if first_or_not == 1:
          round_num += 1
      
      if len(opponent_history)-1 == round_num:
          return 1
      elif len(opponent_history) < 1:
          return 0
      else:
          return opponent_history[-1]
  
subject: Create kato.py