{"ast_node_type":"function","tokens":[{"end":73,"kind":"keyword","start":0,"text":"fn"}]}
    fn from(ops: &Stack<'_, KleeneToken>) -> SmallVec<[KleeneToken; 1]> {
impl From<&Stack<'_, KleeneToken>> for SmallVec<[KleeneToken; 1]> {
        let mut ops: SmallVec<[KleeneToken; 1]> = ops.cloned().collect();