code: def count(self, *args, **kw):
          
          obj = args[0]
          try:
              memo_dict = obj._memo[self.method_name]
          except KeyError:
              self.miss = self.miss + 1
          else:
              key = self.keymaker(*args, **kw)
              if key in memo_dict:
                  self.hit = self.hit + 1
              else:
                  self.miss = self.miss + 1
docs: Counts whether the computed key value is already present
             in the memoization dictionary (a hit) or not (a miss).