code: public static function fromFile(string $filename, ?string $identifier): Configuration
      {
          if ($identifier === null) {
              $pathinfo = pathinfo($filename);
  
              if (!isset($pathinfo['extension'])) {
                  throw new \InvalidArgumentException('The filename "' . $filename . '" is missing an extension and cannot be auto-detected.');
              }
  
              $identifier = strtolower($pathinfo['extension']);
          }
          
          $reader = static::getReader($identifier);
  
          return new Configuration($reader->loadFile($filename));
      }
docs: Creates a Configuration based on the file by the provided $filename.
  
  @param string $filename
  @param string|null $identifier
  
  @throws \InvalidArgumentException if the provided filename i missing an extension
  
  @return Configuration