code: def list(self, pattern='*'):
      
      if self._group_dict is None:
        self._group_dict = collections.OrderedDict(
            (group.id, group) for group in self._client.list_groups())
  
      return [group for group in self._group_dict.values()
              if fnmatch.fnmatch(group.display_name, pattern)]
docs: Returns a list of groups that match the filters.
  
      Args:
        pattern: An optional pattern to filter the groups based on their display
            name. This can include Unix shell-style wildcards. E.g.
            ``"Production*"``.
  
      Returns:
        A list of Group objects that match the filters.