code: public EvaluationResult getAttribute(String contextPath,
                                           Node namespaceNode, URI type,
                                           String xpathVersion) {
          if (finder != null) {
              return finder.findAttribute(contextPath, namespaceNode, type, this,
                                          xpathVersion);
          } else {
              logger.warn(NO_FINDER_MSG);
  
              return new EvaluationResult(BagAttribute.createEmptyBag(type));
          }
      }
docs: Returns the attribute value(s) retrieved using the given XPath
  expression.
  
  @param contextPath the XPath expression to search
  @param namespaceNode the DOM node defining namespace mappings to use,
  or null if mappings come from the context root
  @param type the type of the attribute value(s) to find
  @param xpathVersion the version of XPath to use
  
  @return a result containing a bag either empty because no values were
  found or containing at least one value, or status associated with an
  Indeterminate result