old_contents: class FixFoldStrategy:
      """This strategy folds every time there is a small card available."""
      def __init__(self, N=3):
          self.N = N
      def play(self, info):
          if info.bestFold(self.player)[1] > self.N:
              return 'Hit me'
          else:
              return 'fold'
  
  class RatioFoldStrategy:
      """This strategy folds more readily as their stack grows worse"""
      def __init__(self, N=4):
          self.N = N
      def play(self, info):
          if info.bestFold(self.player)[1]*self.N > sum([s*s for s in self.player.stack]):
              return 'Hit me'
          else:
              return 'fold'
  
new_contents: class FixFoldStrategy:
      """This strategy folds every time there is a small card available."""
      def __init__(self, N=3):
          self.N = N
      def play(self, info):
          if info.bestFold(self.player)[1] > self.N:
              return 'Hit me'
          else:
              return 'fold'
  
  class RatioFoldStrategy:
      """This strategy folds more readily as their stack grows worse"""
      def __init__(self, N=4):
          self.N = N
      def play(self, info):
          if info.bestFold(self.player)[1]*self.N > sum([s*s for s in self.player.stack]):
              return 'Hit me'
          else:
              return 'fold'
  
  class CardCounter:
      """This strategy folds based on card counting expectation values."""
      def __init__(self, scared=0.23):
          from collections import Counter
          self.Counter = Counter
          self.scared = scared
      def play(self, info):
          c = self.Counter(info.deck)
          if info.bestFold(self.player)[1] > self.scared*sum([s*c[s] for s in c])/len(info.deck) + sum([s*c[s]/len(info.deck) for s in self.player.stack]):
              return 'Hit me'
          else:
              return 'fold'
  
subject: Add a simple card counting strategy