private Either <string, int> Validate(UpdateIngredient command) =>
GreatThanZero(command.Id)
.ToEither("O id para deletar tem que ser maior que 0");
public Task <Either <string, Unit> > Handle(UpdateIngredient command) =>
Validate(command)
.Match <Task <Either <string, Unit> > >(
async id => await _ingredientRepository.Update(new Ingredient(id, command.Name, command.Value)),
(v) => Task.FromResult(new Either <string, Unit>(v))
);