More flexible implementation of summing-method

Test.java

public class Test {

  public static void main(String[] args) {
    final ArrayList<Double> list = new ArrayList<>();
    list.add(1.3);
    list.add(1.4);
    list.add(1.7);
    list.add(2.3);
    flexibleSum(list);
  }

  public static void flexibleSum(final Iterable<Double> values) {
    double sum = 0;
    for (final double d : values) {
      sum += d;
    }
    System.out.println(Double.toString(sum));
  }
}