private static String getXmlElementNamespace(final XmlElement parentElement) {
    if (parentElement instanceof XmlTag) {
      return ((XmlTag)parentElement).getNamespace();
    }
    if (parentElement instanceof XmlAttribute) {
      return ((XmlAttribute)parentElement).getNamespace();
    }
    if (parentElement instanceof XmlFile) {
      final XmlDocument document = ((XmlFile)parentElement).getDocument();
      if (document != null) {
        final XmlTag tag = document.getRootTag();
        if (tag != null) {
          return tag.getNamespace();
        }
      }
      return "";
    }
    throw new AssertionError("Can't get namespace of " + parentElement);
  }
private static String getXmlElementNamespace(final XmlElement parentElement)