docs: private static ClassLoader getParentLoader() {
          // check whether thread context loader can "see" Groovy Script class
          ClassLoader ctxtLoader = Thread.currentThread().getContextClassLoader();
          try {
              Class<?> c = ctxtLoader.loadClass(Script.class.getName());
              if (c == Script.class) {
                  return ctxtLoader;
              }
          } catch (ClassNotFoundException cnfe) {
              /* ignore */
          }
          // exception was thrown or we get wrong class
          return Script.class.getClassLoader();
      }