code: def _init_multi_count_metrics(self, pplan_helper):
      
      # inputs
      to_in_init = [self.metrics[i] for i in self.inputs_init
                    if i in self.metrics and isinstance(self.metrics[i], MultiCountMetric)]
      for in_stream in pplan_helper.get_my_bolt().inputs:
        stream_id = in_stream.stream.id
        global_stream_id = in_stream.stream.component_name + "/" + stream_id
        for metric in to_in_init:
          metric.add_key(stream_id)
          metric.add_key(global_stream_id)
      # outputs
      to_out_init = [self.metrics[i] for i in self.outputs_init
                     if i in self.metrics and isinstance(self.metrics[i], MultiCountMetric)]
      for out_stream in pplan_helper.get_my_bolt().outputs:
        stream_id = out_stream.stream.id
        for metric in to_out_init:
          metric.add_key(stream_id)
docs: Initializes the default values for a necessary set of MultiCountMetrics