old_contents: 
  
  class Rule(object):
  
      def __init__(self, trigger, actions):
          self.trigger = trigger
          print "trigger: %s" % trigger
          self.code = []
          time = 0
          for a in actions:
              print "action: %s" % a
              if a == 'back':
                  action = ('reverse', 40)
              elif a == 'stop':
                  action = (None, 0)
              else:   # forward, left, right, speak, light-*
                  action = (a, 40)
              self.code.append(time)
              self.code.append(action)
              time += 0.5
          print "code: %s" % self.code
  
  class RuleEngine(object):
  
      def __init__(self, control):
          self.control = control
          self.rules = []
  
      def check(self, color, touch, direction):
          for rule in self.rules:
              if (rule.trigger == 'collision' and touch) \
                     or (rule.trigger == 'dark ground' and color < 10)  \
                     or (rule.trigger == 'light ground' and color > 10):
                  self.control.program(*rule.code)
  
      def activate(self, rules):
          self.rules = rules
  
new_contents: 
  
  class Rule(object):
  
      def __init__(self, trigger, actions):
          self.trigger = trigger
          print "trigger: %s" % trigger
          self.code = []
          time = 0
          for a in actions:
              print "action: %s" % a
              if a == 'back':
                  action = ('reverse', 40)
              elif a == 'stop':
                  action = (None, 0)
              else:   # forward, left, right, speak, light-*
                  action = (a, 40)
              self.code.append(time)
              self.code.append(action)
              time += 0.5
          print "code: %s" % self.code
  
  class RuleEngine(object):
  
      def __init__(self, control):
          self.control = control
          self.rules = []
  
      def check(self, color, touch, direction):
          for rule in self.rules:
              if (rule.trigger == 'collision' and touch) \
                     or (rule.trigger == 'dark ground' and color < 40)  \
                     or (rule.trigger == 'light ground' and color >= 40):
                  self.control.program(*rule.code)
  
      def activate(self, rules):
          self.rules = rules
  
subject: Decrease sensitivity of dark ground checking.