Hi!

I'm parsing a series of gbff taken from NCBI. However, some of them don't have the DNA sequence inside (e.g.: see the .gbff.gz [here][1]).

What I want to do is to skip these files, but I dont know what to call on Bio::SeqIO. Could anyone just tell me what should I call?

A snippet of my code is:

```
my $in=Bio::SeqIO->new(-file=>"$mygbkff",-format=>'genbank',-alphabet=>"dna");

while (my $seq=$in->next_seq){
    for my $feat ($seq -> get_SeqFeatures){
        next unless (($feat->primary_tag eq "CDS") and (defined $feat->spliced_seq->seq)); #this was my attempt at finding only cds that had sequences annotated
        print "\>";
        print $feat->spliced_seq->seq,"\n";
    }
}
```

 [1]: ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCF_000149425.1_ASM14942v1
Adding this as an answer as requested.

The solution was, rather than verifying if `$feat` is defined, to verify if `$seq` was defined:

```
my $in=Bio::SeqIO->new(-file=>"$mygbkff",-format=>'genbank',-alphabet=>"dna");

while (my $seq=$in->next_seq){
    next unless defined $seq->seq;#This ignores those sequences whose DNA was missing
    for my $feat ($seq -> get_SeqFeatures){
        next unless (($feat->primary_tag eq "CDS") and (defined $feat->spliced_seq->seq)); #this was my attempt at finding only cds that had sequences annotated
        print "\>";
        print $feat->spliced_seq->seq,"\n";
    }
}
```