public static function Now(
      \DateTimeZone $timezone = null, bool $useDayStart = false, bool $useDayEnd = false ) : DateTime
   {

      $dt = new DateTime( 'now', $timezone );

      if ( $useDayStart )
      {
         $dt->setTime( 0, 0, 0 );
      }
      else if ( $useDayEnd )
      {
         $dt->setTime( 23, 59, 59 );
      }

      return $dt;

   }