public function get_groups()
 {
     static $groups = null;
     if (!$this->tenant_domain) {
         return;
     }
     if (is_null($groups)) {
         AADSSO_GraphHelper::$tenant_id = $this->tenant_domain;
         AADSSO_GraphHelper::$settings = $this;
         $groups = AADSSO_GraphHelper::getGroups();
     }
     return $groups;
 }