Piwik\Plugins\UsersManager\Model::setSuperUserAccess PHP Method

    public function setSuperUserAccess($userLogin, $hasSuperUserAccess)
    {
        $this->updateUserFields($userLogin, array('superuser_access' => $hasSuperUserAccess ? 1 : 0));
    }

 /**
  * Enable or disable Super user access to the given user login. Note: When granting Super User access all previous
  * permissions of the user will be removed as the user gains access to everything.
  *
  * @param string   $userLogin          the user login.
  * @param bool|int $hasSuperUserAccess true or '1' to grant Super User access, false or '0' to remove Super User
  *                                     access.
  * @throws \Exception
  */
 public function setSuperUserAccess($userLogin, $hasSuperUserAccess)
 {
     Piwik::checkUserHasSuperUserAccess();
     $this->checkUserIsNotAnonymous($userLogin);
     $this->checkUserExists($userLogin);
     if (!$hasSuperUserAccess && $this->isUserTheOnlyUserHavingSuperUserAccess($userLogin)) {
         $message = Piwik::translate("UsersManager_ExceptionRemoveSuperUserAccessOnlySuperUser", $userLogin) . " " . Piwik::translate("UsersManager_ExceptionYouMustGrantSuperUserAccessFirst");
         throw new Exception($message);
     }
     $this->model->deleteUserAccess($userLogin);
     $this->model->setSuperUserAccess($userLogin, $hasSuperUserAccess);
 }