private static void RemoveUnnecessaryExtAttr(OpenXmlElement node, OpenXmlElement newnode)
 {
     // Reconstruct the _nsMappings for the new node based on the original node
     node.MakeSureParsed();
     if (newnode.NamespaceDeclField != null && node.NamespaceDeclField != null)
     {
         newnode.NamespaceDeclField = new List <KeyValuePair <string, string> >(node.NamespaceDeclField);
     }
 }