File (@NotNull File root) { final String path = root.getAbsolutePath(); LOG.assertTrue(root.exists(), "Helpers root does not exist " + path); for (String child : List.of("generator3", "pycharm", "pycodestyle.py", "pydev", "syspath.py", "typeshed")) { LOG.assertTrue(new File(root, child).exists(), "No '" + child + "' inside " + path); } return root; }