docs: public void addPackageFromDrl(final Reader source,
                                    final Reader dsl) throws DroolsParserException,
              IOException {
          this.resource = new ReaderResource(source, ResourceType.DSLR);
  
          final DrlParser parser = new DrlParser(configuration.getLanguageLevel());
          final PackageDescr pkg = parser.parse(source, dsl);
          this.results.addAll(parser.getErrors());
          if (!parser.hasErrors()) {
              addPackage(pkg);
          }
          this.resource = null;
      }