code: def register(self, class_path):
          
          if class_path in self._metricsets:
              return
          else:
              try:
                  class_obj = import_string(class_path)
                  self._metricsets[class_path] = class_obj(self)
              except ImportError as e:
                  logger.warning("Could not register %s metricset: %s", class_path, compat.text_type(e))
docs: Register a new metric set
          :param class_path: a string with the import path of the metricset class