Adding Custom Product Attribute and Variable in WooCommerce Programatically

can you please let me know how I can add Custom Product Attribute and Variable in WooCommerce Programatically? I know this easy to be done in Woocommerce GUI but I need to do this through functions.php

I have a Attribute Called “Class” and Some Variables as [A,B,C,D] now I would like to add them to the Cart and Shop page, I already tried this function but it didn’t add any thing to the page:

function woocommerce_variable_add_to_cart() {
   //Type attribute
    $product_attributes['type'] = array(
        //Make sure the 'name' is same as you have the attribute
        'name' => htmlspecialchars(stripslashes('Class')),
        'value' => $attributes,
        'position' => 1,
        'is_visible' => 1,
        'is_variation' => 1,
        'is_taxonomy' => 0
    );

//Add as post meta
update_post_meta($post_id, '_product_attributes', $product_attributes);

}

Thanks