Template CSS for AMP

I asked a question here: https://ampforwp.com/tutorials/article/override-blacklist-sanitizer/ but didn ‘t get an answer

This code does not enable custom plugin

add_action(‘amp_post_template_css’,’new_css_for_form’,999);
function new_css_for_form(){ ?>
.amp-wp-content form>div {
display:none;
}

All I see is an extra {
But maybe something else?