Adding Onesignal To Functions.php WordPress

functions.php

add_filter('onesignal_send_notification', 'onesignal_send_notification_filter', 10, 4);
   function onesignal_send_notification_filter($fields, 
   $new_status, $old_status, $post) {
   $fields['data'] = array(
   "id" => $post->ID,
   "category" => "pemberitahuan",
   "silent" => false, 
 );

$fields['isAndroid'] = true;
return $fields;
}