Sorting not working

How do I sort the products?



$args = array(

        'posts_per_page' => $atts['per_page'],

        'paged' => $paged, // Use the specified current page

        'post_type' => 'product',

        'post_status' => 'publish',

        'ignore_sticky_posts' => 1,

        'post__not_in' => array(get_the_ID()), // Exclude the current product

        'tax_query' => array(

            array(

                'taxonomy' => 'product_cat',

                'field'    => 'id',

                'terms'    => $category_id,

            ),

        ),

    );

    if($sort_by === 'price') {

        $args['orderby'] = 'meta_value_num';

        $args['meta_key'] = '_price';

        $args['order'] = 'ASC';

    } else if($sort_by === 'price-desc') {

        $args['orderby'] = 'meta_value_num';

        $args['meta_key'] = '_price';

        $args['order'] = 'DESC';

    } else {

        $args['orderby'] = $sort_by;

    }

    $query = new WP_Query($args);

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