can't build example with nickel.rs 0.9

[cnd]

    router.get("/", middleware! { |req, mut response|
      let mut data = HashMap::new();
      let cook = format!("{:?}", CookieSession::get_mut(req, &mut response));

error[E0308]: mismatched types
  --> src/handler.rs:24:57
   |
24 |       let cook = format!("{:?}", CookieSession::get_mut(req, &mut response));
   |                                                         ^^^ expected struct `nickel::request::Request`, found struct `nickel::Request`
   |
   = note: expected type `&mut nickel::request::Request<'_, '_, _>`
   = note:    found type `&'r mut nickel::Request<'mw, 'conn, _>`

error[E0308]: mismatched types
  --> src/handler.rs:24:62
   |
24 |       let cook = format!("{:?}", CookieSession::get_mut(req, &mut response));
   |                                                              ^^^^^^^^^^^^^ expected struct `nickel::response::Response`, found struct `nickel::Response`
   |
   = note: expected type `&mut nickel::response::Response<'_, _>`
   = note:    found type `&mut nickel::Response<'mw, _>`