docs: private void generateScenes(final Metadata m, final Element e) {
          final Element scenesElement = new Element("scenes", NS);
          for (final Scene scene : m.getScenes()) {
              final Element sceneElement = new Element("scene", NS);
              addNotNullElement(sceneElement, "sceneTitle", scene.getTitle());
              addNotNullElement(sceneElement, "sceneDescription", scene.getDescription());
              addNotNullElement(sceneElement, "sceneStartTime", scene.getStartTime());
              addNotNullElement(sceneElement, "sceneEndTime", scene.getEndTime());
              if (!sceneElement.getChildren().isEmpty()) {
                  scenesElement.addContent(sceneElement);
              }
          }
          if (!scenesElement.getChildren().isEmpty()) {
              e.addContent(scenesElement);
          }
      }