code: public ElemTemplateElement appendChildElem(ElemTemplateElement newChild)
    {
  
      int type = ((ElemTemplateElement) newChild).getXSLToken();
  
      switch (type)
      {
      case Constants.ELEMNAME_ATTRIBUTE :
        break;
      default :
        error(XSLTErrorResources.ER_CANNOT_ADD,
              new Object[]{ newChild.getNodeName(),
                            this.getNodeName() });  //"Can not add " +((ElemTemplateElement)newChild).m_elemName +
  
      //" to " + this.m_elemName);
      }
  
      return super.appendChild(newChild);
    }
docs: Add a child to the child list.
  <!ELEMENT xsl:attribute-set (xsl:attribute)*>
  <!ATTLIST xsl:attribute-set
  name %qname; #REQUIRED
  use-attribute-sets %qnames; #IMPLIED
  >
  
  @param newChild Child to be added to this node's list of children
  
  @return The child that was just added to the list of children
  
  @throws DOMException