Add Else Statement to this Function

How can I add an else statement to this shortcode function so that if there are no jobs postings, the output would be “There are no listings at this time.”

/* Jobs Widget Shortcode */

function vantage_jobs_posts_shortcode($atts, $content = null) {

global $post;

extract(shortcode_atts(array(
‘category_name’ => ‘jobs’,
‘num’ => ‘5’,
‘order’ => ‘DESC’,
‘orderby’ => ‘post_date’,
), $atts));

$args = array(
‘category_name’ => $category_name,
‘posts_per_page’ => $num,
‘order’ => $order,
‘orderby’ => $orderby,
);

$output = ”;

$posts = get_posts($args);

foreach($posts as $post) {

setup_postdata($post);

$output .= ‘‘.get_the_title().’
‘.get_the_date().’

‘;

}

wp_reset_postdata();

return ”. $output .”;

}
add_shortcode(‘vantage_jobs_posts’, ‘vantage_jobs_posts_shortcode’);