code: def add_metric_names(self, names):
          "Add `names` to the inner metric names."
          if hasattr(self, '_added_met_names'): self._added_met_names += names
          else:                                 self._added_met_names  = namef add_metric_names(self, names):
          "Add `names` to the inner metric names."
          if hasattr(self, '_added_met_names'): self._added_met_names += names
          else:                                 self._added_met_names  = names
docs: Add `names` to the inner metric names.