code: def list_groups(self, filtr=None):
          
          return self.service.list_groups(
              filtr, self.url_prefix, self.auth, self.session,
              self.session_send_opts)
docs: Get the groups the logged in user is a member of.
  
          Optionally filter by 'member' or 'maintainer'.
  
          Args:
              filtr (optional[string|None]): ['member'|'maintainer'] or defaults to None.
          Returns:
              (list[string]): List of group names.
  
          Raises:
              requests.HTTPError on failure.