code: def discard(self, rule, count=1):
          
          assert isinstance(rule, ClassifierRule)
          assert isinstance(count, int) and count >= 0
  
          rule = self.get(rule)
          if rule is None:
              return False
  
          # Only actually remove the rule if its numerosity drops below 1.
          rule.numerosity -= count
          if rule.numerosity <= 0:
              # Ensure that if there is still a reference to this rule
              # elsewhere, its numerosity is still well-defined.
              rule.numerosity = 0
  
              del self._population[rule.condition][rule.action]
              if not self._population[rule.condition]:
                  del self._population[rule.condition]
              return True
  
          return False
docs: Remove one or more instances of a rule from the classifier set.
          Return a Boolean indicating whether the rule's numerosity dropped
          to zero. (If the rule's numerosity was already zero, do nothing and
          return False.)
  
          Usage:
              if rule in model and model.discard(rule, count=3):
                  print("Rule numerosity dropped to zero.")
  
          Arguments:
              rule: A ClassifierRule instance whose numerosity is to be
                  decremented.
              count: An int, the size of the decrement to the rule's
                  numerosity; default is 1.
          Return:
              A bool indicating whether the rule was removed altogether from
              the classifier set, as opposed to simply having its numerosity
              decremented.