{"ast_node_type":"function","tokens":[{"end":72,"kind":"keyword","start":0,"text":"fn"}]}
    fn from_iter<I: IntoIterator<Item = (Idx<V>, T)>>(iter: I) -> Self {
impl<T, V> FromIterator<(Idx<V>, T)> for ArenaMap<Idx<V>, T> {
        let mut this = Self::new();