{"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"Ok(Err(token))"}]}
        Ok(Err(token)) => match parse_kleene_op(iter, token.span) {
        // #1 is a separator followed by #2, a KleeneOp
            // #2 is the `?` Kleene op, which does not take a separator (error)