code: def add_group(self, group_name, group_client_names):
          
          group_configs = self._resources_spec.get('groups', {})
          group_configs[group_name] = group_client_names
          self._resources_spec['groups'] = group_configs
          self._init_groups()
docs: Add a new :class:`ClientGroup` to container groups member.
  
          Add the group named *group_name* with sequence of client names to the
          container groups member. From there it will be wrapped appropriately
          in the higher-level thread-safe container.