# Add start and end if necessary
unshift( @chain, $self->start ) unless $chain[0] eq $self->start;
push( @chain, $self->end ) unless $chain[-1] eq $self->end;
- $DB::single = 1;
foreach my $idx ( 0 .. $#chain-1 ) {
$self->add_path( $chain[$idx], $chain[$idx+1], $sig );
}