code: public function get(string $sessionIdentifier): string
      {
          if (!$this->sessionExists($sessionIdentifier)) {
              throw new SessionNotFoundException();
          }
  
          return self::$files[$sessionIdentifier]['data'];
      }
docs: Fetches the encrypted session data based on the session identifier.
  
  @throws \PHPSess\Exception\SessionNotFoundException
  @param  string $sessionIdentifier The session identifier
  @return string The encrypted session data