The example actually does handle all errors, because the values are of type `Either` and the composition functions take this into account. If you would like to

The example actually does handle all errors, because the values are of type `Either` and the composition functions take this into account. If you would like to handle a particular error sitation explicitly, e.g. to enrich it with context or to transform one error into another, you may use `MapLeft` or `Swap`.