CTP custom post per page

CTP_custom_post_per_page.php

<?php
// Posts per page on CPT
function cs_custom_posts_per_page_CPT( $query ) {
    switch ( $query->query_vars['post_type'] ) {
        case 'album-de-fotos':
            $query->query_vars['posts_per_page'] = 9;
            break;
        case 'loja':
            $query->query_vars['posts_per_page'] = 15;
            break;
        default:
            break;
    }
    return $query;
}
add_filter( 'pre_get_posts', 'cs_custom_posts_per_page_CPT' );
?>