Db.save fails when autogenerated keys are missing

[atiqsayyed]

[ERROR] [07/08/2017 19:39:20.831] [tims-system-akka.actor.default-dispatcher-4] [akka.actor.ActorSystemImpl] Error during processing of request: 'head of empty list'. Completing with 500 Internal Server Error response. To change default exception handling behavior, provide a custom ExceptionHandler.

java.util.NoSuchElementException: head of empty list
	at scala.collection.immutable.Nil$.head(List.scala:420)
	at scala.collection.immutable.Nil$.head(List.scala:417)
	at sorm.driver.StdModify$$anonfun$insertAndGetGeneratedKeys$4.apply(StdModify.scala:26)
	at sorm.driver.StdModify$$anonfun$insertAndGetGeneratedKeys$4.apply(StdModify.scala:26)
	at embrace.package$EmbraceAny$.$$extension(package.scala:6)
	at sorm.driver.StdModify$class.insertAndGetGeneratedKeys(StdModify.scala:26)
	at sorm.driver.Mysql.insertAndGetGeneratedKeys(Mysql.scala:7)
	at sorm.mappings.EntityMapping.save(EntityMapping.scala:66)
	at sorm.Instance$Api$$anonfun$save$1.apply(Instance.scala:130)
	at sorm.Instance$Api$$anonfun$save$1.apply(Instance.scala:129)
	at embrace.package$EmbraceAny$.$$extension(package.scala:6)
	at sorm.core.Connector$$anonfun$withConnection$1.apply(Connector.scala:28)
	at sorm.core.Connector$$anonfun$withConnection$1.apply(Connector.scala:28)
	at sorm.pooling.ConnectionPool$class.withConnection(ConnectionPool.scala:22)
	at sorm.pooling.C3p0ConnectionPool.withConnection(C3p0ConnectionPool.scala:9)
	at sorm.core.Connector.withConnection(Connector.scala:28)
	at sorm.Instance$Api$class.save(Instance.scala:129)
	at sorm.Instance.save(Instance.scala:30)

In trait StdModify
  def insertAndGetGeneratedKeys
    ( table : String, values : Iterable[(String, Any)] )
    : Seq[Any]
    = values.toStream.unzip $$ (Insert(table, _, _)) $ statement $ connection.executeUpdateAndGetGeneratedKeys $ (_.**head**)

what if the executeUpdateAndGetGeneratedKeys returns an empty list?