class WPDesk_Post_Not_Exists_Exception extends \Exception {
}

/**
 * @return \WP_Post
 * @throws \WPDesk_Post_Not_Exists_Exception
 */
function get_wpdesk_post() {
    $post = get_post(123);
    if ($post) {
        return $post;
    }

    throw new WPDesk_Post_Not_Exists_Exception('WPDesk post 123 is not available in the database');
}

/**
 * @return string When post not exists returns default post title.
 */
function get_wpdesk_post_title() {
    try {
      return get_wpdesk_post()->post_title;
    } catch (\WPDesk_Post_Not_Exists_Exception $not_exists) {
      return __('Some placeholder title', 'some-text-domain');
    }
}

function display_wpdesk_title() {
    echo get_wpdesk_post_title();
}

display_wpdesk_title();