* Receives the value of the ODFDOM attribute representation <code>SmilValuesAttribute</code> , See {@odf.attribute smil:values}
   *
   * @return - the <code>String</code> , the value or <code>null</code>, if the attribute is not set and no default value defined.
   */
  public String getSmilValuesAttribute() {
    SmilValuesAttribute attr = (SmilValuesAttribute) getOdfAttribute(OdfDocumentNamespace.SMIL, "values");
    if (attr != null) {
      return String.valueOf(attr.getValue());
    }
    return null;
  }