@SafeVarargs
    public static <T> Predicate<T> in(T... args) {
        return input -> {
            if (input == null) {
                for (T t : args) {
                    if (t == null) {
                        return true;
                    }
                }
            } else {
                for (T t : args) {
                    if (input.equals(t)) {
                        return true;
                    }
                }
            }
            return false;
        };
    }
Returns a predicate which returns true if the input is contained within
the given var args.

@param args the array to query
@param <T> the type
@return a predicate
helper/src/main/java/me/lucko/helper/function/Predicates.java