code: public function convertToPhpValue($value)
      {
          if (!is_array($value)
              || !isset($value['date'])
              || !$value['date'] instanceof \MongoDate
              || !isset($value['tz'])
          ) {
              return null;
          }
          
          $timestamp = $value['date']->sec;
          $date = new \DateTime('@'.$timestamp);
          $date->setTimezone(new \DateTimeZone($value['tz']));
          return $date;
      }
docs: Converts a TimezoneAwareDate array to a \DateTime Object.
  
  Returns <i>NULL</i>, if <code>$value</code> is an unknown format.
  
  @param array $value
  @return NULL|\DateTime