it.agilelab.bigdata.wasp.consumers.spark.strategies.gdpr
(optional) output dataframe of the strategy (it is None only if the strategy has no writer)
Some(error) if an error happened during materialization; None otherwise
the wanted outcome of the strategy. This means that if the maybeError is not None and the hook does not have a "recovery" logic, it should always return a Failure wrapping the input error.