How to avoid nested fold in when calling multiple Future with DartZ?

Question

I have a piece of code that look like this:

final Either<Failure, Unit> resA = await deleteA();

resA.fold(
  (failure) => handleFailure(),
  (success) async {
    final Either<Failure, Unit> resB = await deleteB();
    resB.fold(
      (failure) => handleFailure(),
      (success) => handleSuccess(),
    );
  },
);

Basically, I want to call a first function, that returns either a Failure or a Unit (the success value doesn't matter).

Then, if the first function succeeded, I want to call another function, that also return either a Future or a Unit.

How could I do to avoid this ugly nested call of fold inside another fold?

I'm working with the package dartz, which is really cool, but lacks of documentation.