function getSubstitution()
 {
     $subs = array();
     $aclman =& Docebo::user()->getAclManager();
     $user = $aclman->getUser($this->id_user, false);
     $subs['[display_name]'] = $user[ACL_INFO_LASTNAME] . $user[ACL_INFO_FIRSTNAME] ? $user[ACL_INFO_LASTNAME] . ' ' . $user[ACL_INFO_FIRSTNAME] : $aclman->relativeId($user[ACL_INFO_USERID]);
     $subs['[username]'] = $aclman->relativeId($user[ACL_INFO_USERID]);
     $subs['[firstname]'] = $user[ACL_INFO_FIRSTNAME];
     $subs['[lastname]'] = $user[ACL_INFO_LASTNAME];
     //variable fields
     require_once $GLOBALS['where_framework'] . '/lib/lib.field.php';
     $temp = new FieldList();
     $fields = $temp->getFlatAllFields();
     foreach ($fields as $key => $value) {
         $subs['[userfield_' . $key . ']'] = $temp->showFieldForUser($this->id_user, $key);
     }
     return $subs;
 }