Limit customer to purchase only 3 products per vendor

I am trying to limit 3 orders per vendor on my woocommerce wc vendors market place. I am new to php, managed to write the below code. But it is not working. I am i missing anything.

add_filter( ‘woocommerce_add_cart_item_data’, ‘woo_custom_add_to_cart’ );
// function to execute
function woo_custom_add_to_cart( $cart_item_data ) {
global $woocommerce;
$items = $woocommerce->cart->get_cart(); //getting cart items

$_product = array();  //getting all the products from the cart
foreach($items as $item => $values) {
$_product[] = $values[‘data’]->post;
}

$_vendor_ids_in_cart = array();

if (count ($_product[]) === 3) { //if cart has 3 products, getting all the vendor id's
    for($x = 0; $x <= count($_product); $x++) {
        $_vendor_ids_in_cart[] = get_post_field( 'post_author', $_product[$x]->ID);
    }
    
//getting vendor id for the current product that is being added to cart
   $prodId = (int) apply_filters( 'woocommerce_add_to_cart_product_id', $_GET['add-to-cart'] );
    $product_added_vendor_id = get_post_field( 'post_author', $prodId );

//getting the count of products each vendor has in the cart
    $count_of_each_vendor_id = array_count_values($_vendor_ids_in_cart);

//count of vendor id's 
    $cnt_how_many_times_vendor_id_exits = $count_of_each_vendor_id[product_added_vendor_id];

//check the count, if the count of the cart items are greater than 3 for a single vendor
    if ($cnt_how_many_times_vendor_id_exits > 3) {
        $woocommerce->cart->empty_cart();
        wc_add_notice(  __("You can add only 3 order items from 1 vendor !", "wcvendors"));
    }
}
return $cart_item_data; 
}