docs: public static <T> Callable<T> memoizeCallable(final Callable<T> s, final Cacheable<T> cache) {
  
          return () -> cache.soften()
                            .computeIfAbsent("k", a -> {
  
                                return ExceptionSoftener.softenCallable(s)
                                                        .get();
  
                            });
      }