public function cleanClothes() { // drive to laundry $this->balance = $this->taxi->drive($this->balance, $this->place); // clean all dirty clothes $cleanClothes = $this->clothes->getCleanClothes() + $this->clothes->getDirtyClothes(); $this->clothes->setCleanClothes($cleanClothes); // go back to home $this->balance = $this->taxi->drive($this->balance, $this->home); }