code: public function save(array $rates)
      {
          /**
           * @var RateInterface $rate
           */
          foreach ($rates as $rate) {
              $this->rates[$this->getRateKey($rate->getCurrencyCode(), $rate->getDate(), $rate->getRateType(), $rate->getSourceName())] = $rate;
          }
  
          usort($this->rates, function (RateInterface $rate1, RateInterface $rate2) {
              return ($rate1->getDate() > $rate2->getDate()) ? -1 : 1;
          });
  
          $data = '';
  
          /**
           * @var RateInterface $rate
           */
          foreach ($this->rates as $rate) {
              $data .= $this->toJson($rate)."\n";
          }
  
          file_put_contents($this->pathToFile, $data, LOCK_EX);
  
          $this->load();
      }
docs: {@inheritdoc}