code: def process(self, metrics, config):
          
          LOG.debug("Process called")
          for metric in metrics:
              metric.tags["instance-id"] = config["instance-id"]
          return metrics
docs: Processes metrics.
  
          This method is called by the Snap deamon during the process phase
          of the execution of a Snap workflow.  Examples of processing metrics
          include applying filtering, max, min, average functions as well as
          adding additional context to the metrics to name just a few.
  
          In this example we are adding a tag called 'context' to every metric.
  
          Args:
              metrics (obj:`list` of `snap_plugin.v1.Metric`):
                  List of metrics to be processed.
  
          Returns:
              :obj:`list` of `snap_plugin.v1.Metric`:
                  List of processed metrics.