/// book_reviews.insert("The Adventures of Sherlock Holmes", "Eye lyked it alot.");
///
/// // check for a specific one.
-/// if !book_reviews.contains_key(&("Les Misérables")) {
+/// if !book_reviews.contains_key("Les Misérables") {
/// println!("We've got {} reviews, but Les Misérables ain't one.",
/// book_reviews.len());
/// }
///
/// // oops, this review has a lot of spelling mistakes, let's delete it.
-/// book_reviews.remove(&("The Adventures of Sherlock Holmes"));
+/// book_reviews.remove("The Adventures of Sherlock Holmes");
///
/// // look up the values associated with some keys.
/// let to_find = ["Pride and Prejudice", "Alice's Adventure in Wonderland"];
-/// for book in to_find.iter() {
+/// for book in &to_find {
/// match book_reviews.get(book) {
-/// Some(review) => println!("{}: {}", *book, *review),
-/// None => println!("{} is unreviewed.", *book)
+/// Some(review) => println!("{}: {}", book, review),
+/// None => println!("{} is unreviewed.", book)
/// }
/// }
///
/// // iterate over everything.
-/// for (book, review) in book_reviews.iter() {
-/// println!("{}: \"{}\"", *book, *review);
+/// for (book, review) in &book_reviews {
+/// println!("{}: \"{}\"", book, review);
/// }
/// ```
///
/// vikings.insert(Viking::new("Harald", "Iceland"), 12);
///
/// // Use derived implementation to print the status of the vikings.
-/// for (viking, health) in vikings.iter() {
+/// for (viking, health) in &vikings {
/// println!("{:?} has {} hp", viking, health);
/// }
/// ```