{"ast_node_type":"variable","tokens":[{"end":53,"kind":"keyword","start":0,"text":"let"}]}
    let is_vis = seq.tts.first().map_or(false, |tt| {
    let is_zero_or_one: bool = seq.kleene.op == KleeneOp::ZeroOrOne;
        matches!(tt, mbe::TokenTree::MetaVarDecl { kind: NonterminalKind::Vis, .. })