can’t get a single post to clear upon update

Hi. I’ve written some custom functions into my theme to take advantage of the cache purge capability. I’m able to get the cache cleared on CPT archive pages when a specific custom post type is added or modified. But for the life of me I can’t get it to do a purge on a single page. Can you look over the code I’ve written below and see if I’m doing something obviously wrong?

add_action( 'save_post', 'clean_post_cache_on_save');

function clean_post_cache_on_save( $post_id) {

// check whether the plugin "Pantheon Advanced Page Cache" exists the it's function clean_post_cache exists

if ( ! function_exists( 'pantheon_clear_edge_paths' ) ) {

return;

}

// Ignore revisions, which aren't ever displayed on the site.

$type = get_post_type( $post_id );

if ( $type && 'revision' === $type ) {

return;

}

clean_post_cache( $post_id );

}