{"ast_node_type":"variable","tokens":[{"end":60,"kind":"keyword","start":0,"text":"let"}]}
    let f = a.combine_commutative(b).combine_commutative(c);
    let permutations = [(a, b, c), (a, c, b), (b, a, c), (b, c, a), (c, a, b), (c, b, a)];
    for p in &permutations {