docs: private void generateEmbed(final Metadata m, final Element e) {
          if (m.getEmbed() == null) {
              return;
          }
          final Element embedElement = new Element("embed", NS);
          addNotNullAttribute(embedElement, "url", m.getEmbed().getUrl());
          addNotNullAttribute(embedElement, "width", m.getEmbed().getWidth());
          addNotNullAttribute(embedElement, "height", m.getEmbed().getHeight());
          for (final Param param : m.getEmbed().getParams()) {
              final Element paramElement = addNotNullElement(embedElement, "param", param.getValue());
              if (paramElement != null) {
                  addNotNullAttribute(paramElement, "name", param.getName());
              }
          }
          if (embedElement.hasAttributes() || !embedElement.getChildren().isEmpty()) {
              e.addContent(embedElement);
          }
      }