my $self = shift;
  my $msg  = shift;

  my $fh = $self->{'fh'};

  if(!$self->{'seen_msgs'}->{$msg->id}) {
    print $fh $msg->code(), "\n";
    $self->{'seen_msgs'}->{$msg->id()} = 1;
  }
}


1;

  my $class = shift;
  my $filename = shift;

  my $fh;

  if($filename) {
    $fh = IO::File->new();
    $fh->open(">$filename") or throw("Could not open file $filename.");
    $fh->autoflush();
  } else {
    $fh =\* STDOUT;
  }

  return bless {'fh' => $fh,
                'seen_msgs' => {}}, $class;