code: @Nonnull
    public static XPathExpression createNewXPathExpression (@Nullable final NamespaceContext aNamespaceContext,
                                                            @Nonnull @Nonempty final String sXPath)
    {
      return createNewXPathExpression (createNewXPath (aNamespaceContext), sXPath);
    }
docs: Create a new XPath expression for evaluation using the default
  {@link XPathFactory}.
  
  @param aNamespaceContext
  Namespace context to be used. May be <code>null</code>.
  @param sXPath
  The main XPath string to be evaluated
  @return The {@link XPathExpression} object to be used.
  @throws IllegalArgumentException
  if the XPath cannot be compiled