[Bioperl-l] Why does Bio::DB::GFF::Feature::gff3_string swap start and stop coordinates??

[Cook, Malcolm]

Why does Bio::DB::GFF::Feature::gff3_string swap start and stop
coordinates, 

as in:
  ($start,$stop) = ($stop,$start) if defined($start) && defined($stop)
&& $start > $stop;

I thought it is not legal for a feature to be so composed.  

Anyone know?

Cheers,

Malcolm Cook
Stowers Institute for Medical Research - Kansas City, Missouri