my $next_class = $cur_class->meta->relationship($step)->class;
push @{ $spec->{steps} }, [ $step, $next_class, $index ];
$cur_class = $next_class;
my $next_class = $cur_class->meta->relationship($step)->class;
push @{ $spec->{steps} }, [ $step, $next_class, $index ];
$cur_class = $next_class;