docs: public String getExpandedDRL(final String source,
                                   final DefaultExpanderResolver resolver) throws DroolsParserException {
  
          final Expander expander = resolver.get("*",
                  null);
          final String expanded = expander.expand( source );
          if ( expander.hasErrors() ) {
              String err = "";
              for ( ExpanderException ex : expander.getErrors() ) {
                  err = err + "\n Line:[" + ex.getLine() + "] " + ex.getMessage();
  
              }
              throw new DroolsParserException( err );
          }
          return expanded;
      }