ISOP7.php

<?php
    public function calculate(CarRental $carRental): int
    {
        $startDate = $carRental->getStartDate();
        $endDate = $carRental->getEndDate();
        $days = $startDate->diff($endDate);

        $dayPrice = $this->dateRangePriceCalculator->calculate(
            $days,
            $carRental->getPricePerDay()
        );
        $distancePrice = $this->distancePriceCalculator->calculate(
            $carRental->getDistance(), 
                        $carRental->getPricePerKm()
        );

        return $this->dayDistanceCalculator->calculate(
                        $dayPrice, 
                        $distancePrice
                );
    }