code: protected function retrieve(array $routes, $uri)
      {
          $routes = array_values(array_filter($routes));
  
          if (empty($routes)) {
              $message = 'Route "' . $uri . '" not found';
  
              throw new \UnexpectedValueException($message);
          }
  
          $route = current($routes);
  
          $route[1] = (count($route[1]) > 0) ? array_combine($route[3], $route[1]) : $route[1];
  
          return $route;
      }
docs: Retrieved the specified route from the result.
  
  @throws \UnexpectedValueException
  
  @param  array  $routes
  @param  string $uri
  @return array