If SUMMARY is not set in a recurring event's exception, copy it from the recurring event itself

                exceptions[uid]?.let { eventExceptions ->

                    event.exceptions.addAll(eventExceptions.map { (_,it) -> fromVEvent(it) })

                }

                // make sure that exceptions have at least a SUMMARY

                event.exceptions.forEach { it.summary = it.summary ?: event.summary }

                events += event

            }