def METHOD_NAME(self, nodes: Sequence[BackendNode], **kwargs):  # pylint: disable=unused-argument
    """Add a set of nodes to the group.
    :note: all the nodes *and* the group itself have to be stored.
    :param nodes: a list of `BackendNode` instances to be added to this group
    """
    if not self.is_stored:
        raise ValueError('group has to be stored before nodes can be added')
    if not isinstance(nodes, (list, tuple)):
        raise TypeError('nodes has to be a list or tuple')
    if any(not isinstance(node, BackendNode) for node in nodes):
        raise TypeError(f'nodes have to be of type {BackendNode}')