code: def value(self, key, value=1):
          
          if isinstance(key, six.string_types):
              key = (key, )
          # assert all(isinstance(k, six.string_types) for k in key)
          assert isinstance(key, tuple), "event key type error"
          if key not in self.counters:
              self.counters[key] = self.cls()
          self.counters[key].value(value)
          return self
docs: Set value of a counter by counter key