{"ast_node_type":"variable","tokens":[{"end":32,"kind":"keyword","start":0,"text":"let"}]}
    let attr = attr.map(|attr| {
        parse_string_spanned(call_site.anchor, call_site.ctx, input).into_subtree(call_site);
        parse_string_spanned(call_site.anchor, call_site.ctx, attr).into_subtree(call_site)