def METHOD_NAME(self, group_key):
    members = []
    try:
        api = self.client.members()
        request = api.list(groupKey=group_key)
        while request is not None:
            members_response = request.execute()
            remote_members = members_response.get("members", [])
            members = members + remote_members
            request = api.list_next(request, members_response)
        return members
    except HttpError as e:
        if e.resp.status == 404:
            return members
        raise