What is the error?
I did as it is written in the React book. (It’s in Russian and there are some mistakes there)
I did as it is written in the React book. (It’s in Russian and there are some mistakes there)
React Router has had some major breaking changes in the years since the book was published. My suggestion would be for you to consider following this tutorial from their official documentation instead: Tutorial v6.8.0 | React Router
Cheers,
Kirupa 
спасибо!