code: private void findPluginsForDescriptor(final CommandLinePluginDescriptor<?> pluginDescriptor)
      {
          final ClassFinder classFinder = new ClassFinder();
          pluginDescriptor.getPackageNames().forEach(
                  pkg -> classFinder.find(pkg, pluginDescriptor.getPluginBaseClass()));
          final Set<Class<?>> pluginClasses = classFinder.getClasses();
  
          for (Class<?> c : pluginClasses) {
              if (pluginDescriptor.includePluginClass(c)) {
                  try {
                      final Object plugin = pluginDescriptor.createInstanceForPlugin(c);
                      createArgumentDefinitions(plugin, pluginDescriptor);
                  } catch (InstantiationException | IllegalAccessException e) {
                      throw new CommandLineException.CommandLineParserInternalException("Problem making an instance of plugin " + c +
                              " Do check that the class has a non-arg constructor", e);
                  }
              }
          }
      }
docs: instance each and add its ArgumentDefinitions