def add_group_members(self, members):
        """Add a new group member to the groups list

        :param members: member name
        :type members: str
        :return: None
        """
        if not isinstance(members, list):
            members = [members]

        if not getattr(self, 'group_members', None):
            self.group_members = members
        else:
            self.group_members.extend(members)