code: public function getExtraTime($maxTime = 0)
      {
          if ($maxTime && $this->getExtendedTime()) {
              $secondsNew = $maxTime * $this->getExtendedTime();
              $extraTime = $secondsNew - $maxTime;
              $this->setExtraTime($extraTime);
              return $extraTime;
          }
          return $this->extraTime;
      }
docs: Gets the added extra time
  @param int $maxTime
  @return float