foreach my $e ( @{$graph_data->{'edges'}} ) {
my $from = $e->{$SOURCE_KEY};
my $to = $e->{$TARGET_KEY};
- my $class = $e->{$CLASS_KEY};
+ my $class = $e->{$CLASS_KEY} || 'path';
# We may have more information depending on the class.
if( $class eq 'path' ) {