code: public static <R> Nullable<R> tryOrEmpty(final Callable<R> cmd) {
          try {
              return Nullable.of(cmd.call());
          } catch (Exception e) {
              return Nullable.<R> empty();
          }
      }
docs: Returns a {@code Nullable} with the value returned by {@code action} or an empty {@code Nullable} if exception happens.
  
  @param cmd
  @return