1No vertices, not directed: 2No vertices, directed: 3Directed graph with loops and multi-edges with negative loop: 4Directed graph with loops and multi-edges: 5[ 0 -1 -3 1 6 Inf 6 1 0 -2 2 7 Inf 7 3 2 0 4 9 Inf 8 Inf Inf Inf 0 5 Inf 9 Inf Inf Inf Inf 0 Inf 10 Inf Inf Inf Inf Inf 0 ] 11Directed graph with loops and multi-edges, select vertices 1 and 2: 12[ 0 -2 13 2 0 ] 14Directed graph with loops and multi-edges, select 0 -> 2: 15[ -3 ] 16Directed graph with loops and multi-edges, select none: 17