> Immediate choices are: > > 1) return a 'null' value for the end 'SeqFeaturePostion'. > > 2) Throw a "UnableToProcess" exception and return the location as a > string. Sorry, that should be throw an "UnableToProcess" exception on the 'locations()' method of SeqFeature and include the stringified location (e.g. (1^3)) in the 'reason' string of the exception.