{"ast_node_type":"function","tokens":[{"end":68,"kind":"keyword","start":0,"text":"fn"}]}
    fn extend<T: IntoIterator<Item = CfgAtom>>(&mut self, iter: T) {
impl Extend<CfgAtom> for CfgOptions {
        iter.into_iter().for_each(|cfg_flag| self.insert_any_atom(cfg_flag));