code: public static function suppress($mask = null)
      {
          if (!isset($mask)) {
              $mask = E_WARNING | E_NOTICE | E_USER_WARNING | E_USER_NOTICE | E_DEPRECATED | E_USER_DEPRECATED | E_STRICT;
          }
          $old = error_reporting();
          self::$stack[] = $old;
          error_reporting($old & ~$mask);
  
          return $old;
      }
docs: Suppresses given mask or errors.
  
  @param  int|null $mask Error levels to suppress, default value NULL indicates all warnings and below.
  @return int      The old error reporting level.