How to create a HOC (High Order Function) that wraps getServerSideProps in Next.js?

Question

I found this implementation in Next.js's documentation: https://nextjs.org/docs/authentication

My question is how can I recreate a HOC similar to this one.

What is the structure inside of this function withSession() that wraps getServerSideProps?

export const getServerSideProps = withSession(async function ({ req, res }) {
  // Get the user's session based on the request
  const user = req.session.get('user')

  if (!user) {
    return {
      redirect: {
        destination: '/login',
        permanent: false,
      },
    }
  }

  return {
    props: { user },
  }
})