load(graphs)$
g: create_graph([[1, "a"], [2, "b"], [3, "c"], [4, "d"], [5, "e"], [6, "f"]],
   [[[1, 2], 7],
    [[1, 3], 9],
    [[1, 6], 14],
    [[2, 3], 10],
    [[2, 4], 15],
    [[3, 4], 11],
    [[3, 6], 2],
    [[4, 5], 6],
    [[5, 6], 9]], directed)$

shortest_weighted_path(1, 5, g);
/* [26, [1, 3, 4, 5]] */