def add_nodes(graph, nodes):
    """ Add node(s) to graph

    Args:
        graph (Graph): Graph to add node(s) to
        nodes (list): List of nodes

    Returns:
        Graph: Return the modified graph

    """
    for n in nodes:
        if isinstance(n, tuple):
            graph.node(n[0], **n[1])
        else:
            graph.node(n)
    return graph
