code: public static <T> Predicate<T> in(Collection<? extends T> target) {
      return new InPredicate<T>(target);
    }
docs: Returns a predicate that evaluates to {@code true} if the object reference being tested is a
  member of the given collection. It does not defensively copy the collection passed in, so
  future changes to it will alter the behavior of the predicate.
  
  <p>This method can technically accept any {@code Collection<?>}, but using a typed collection
  helps prevent bugs. This approach doesn't block any potential users since it is always possible
  to use {@code Predicates.<Object>in()}.
  
  @param target the collection that may contain the function input