Custom field to the listings

Hello,

I’m trying to add a custom field to the listings.

I’ve added the following code to have the fields in the backoffice:

add_filter( 'auto_listings_metabox_specs', function ( $fields ) {
    $prefix = '_al_listing_';
    $fields[8] = array(
        'name' => __( 'Co2 uitstoot (WLTP)', 'auto-listings' ),
        'id' => $prefix . 'co2_uitstoot_wltp',
        'type' => 'text',
    );
	$fields[9] = array(
        'name' => __( 'Co2 uitstoot (NEDC2.0)', 'auto-listings' ),
        'id' => $prefix . 'co2_uitstoot_nedc',
        'type' => 'text',
    );
    return $fields;
} );

This works so far.
Then I want to show it on the front end.
I added following code to the specifications.php :

<tr>
      <th>Co2 Uitstoot NEDC</th>
      <td><?php get_post_meta( get_the_ID(), '_al_listing_co2_uitstoot_nedc', true) ?></td>
    </tr>
    <tr>
      <th>Co2 Uitstoot WLTP</th>
      <td><?php get_post_meta( get_the_ID(), 'co2_uitstoot_wltp', true) ?></td>
    </tr>

But the code doesn’t get picked up and get a blanc field.

To get the value of this custom field it is simply a matter of using get_post_meta( get_the_ID(), '_al_listing_custom_field', true) somewhere within the listing template.

The only thing I need to change is the '_al_listing_custom_field' to show the proper fields?

Thanks for the help!