Add a custom tab to woocommerce product page

f.php

<?php

add_filter('woocommerce_product_tabs', 'lame_custom_product_tab_filter', 123);

function lame_custom_product_tab_filter($args){
    $args[] = array(
        'title' => 'Custom tab',
        'priority' => 999,
        'callback' => 'lame_custom_product_tab'
    );
    return $args;
}


function lame_custom_product_tab(){
    echo "this is the value";
}