Exclude specific product category from shop page

I am trying to exclude a specific category from my shop overview page. I found the code below which appeared to work for others but does not work on my site. Is there something missing from the code or something I am overlooking?

I tried inserting it into my functions.php file. 9869 is the category ID I am trying to hide.

/**
* This code should be added to functions.php of your theme
**/
add_filter( ‘pre_get_posts’, ‘custom_pre_get_posts_query’ );

function custom_pre_get_posts_query( $q ) {

if ( ! $q->is_main_query() ) return;
if ( ! $q->is_post_type_archive() ) return;

$q->set( ‘tax_query’, array(array(
‘taxonomy’ => ‘product_cat’,
‘field’ => ‘id’,
‘terms’ => array( 9869 ),
‘operator’ => ‘NOT IN’
)));

remove_filter( ‘pre_get_posts’, ‘custom_pre_get_posts_query’ );

}