code: protected function initialize()
      {
          /** @noinspection MkdirRaceConditionInspection */
          if (!file_exists(dirname($this->pathToFile)) && !mkdir(dirname($this->pathToFile), 0777, true)) {
              throw new RuntimeException(sprintf('Could not create storage file on path "%s".', $this->pathToFile));
          }
  
          if (!file_exists($this->pathToFile) && !(touch($this->pathToFile) && chmod($this->pathToFile, 0777))) {
              throw new RuntimeException(sprintf('Could not create storage file on path "%s".', $this->pathToFile));
          }
  
          if (!is_readable($this->pathToFile)) {
              throw new RuntimeException(sprintf('File on path "%s" for storing rates must be readable.', $this->pathToFile));
          }
  
          if (!is_writable($this->pathToFile)) {
              throw new RuntimeException(sprintf('File on path "%s" for storing rates must be writeable.', $this->pathToFile));
          }
      }
docs: Initializes file storage.
  
  @codeCoverageIgnore