{"ast_node_type":"variable","tokens":[{"end":79,"kind":"keyword","start":0,"text":"let"}]}
    let diamond_acyclic = TestGraph::new(0, &[(0, 1), (0, 2), (1, 3), (2, 3)]);
    let diamond_cyclic = TestGraph::new(0, &[(0, 1), (1, 2), (2, 3), (3, 0)]);