my $self = shift if (defined(caller(1)));

  my $source_id = shift;
  my $species_id = shift;
  my $files       = shift;
  my $release_file   = shift;
  my $verbose       = shift;

  my $file = @{$files}[0];

  my @xrefs;

  local $/ = "\n>";

  my $ipi_io = $self->get_filehandle($file);

  if ( !defined $ipi_io ) {
    print STDERR "ERROR: Could not open $file\n";
    return 1;    # 1 = error
  }

  my %species_tax_id = %{$self->get_taxonomy_from_species_id($species_id)};

  while ( $_ = $ipi_io->getline() ) {
    my $xref;

    my ($header, $sequence) = $_ =~ /^>?(.+?)\n([^>]*)/s or warn("Can't parse FASTA entry: $_\n");

    # deconstruct header
    my @header = split /\|/, $header;
    my ($ipi) = $header[0] =~ /^IPI:(IPI(\d)+(\.\d+)?)/ or warn("Can't deduce IPI identifier from " .  $header[0]);
    my ($ipi_ac, $ipi_ver) = $ipi =~ /(IPI\d+)\.(\d+)/;

    my ($tax_id, $description) = $header[-1] =~ /.*Tax_Id=(\d+)\s+(.*)/;

    # note currently we ignore all the other cross-references in the IPI file

    # only interested in species with the taxonomy ID were looking for
    next if ( !defined $tax_id || !defined $species_tax_id{$tax_id});

    # make sequence into one long string
    $sequence =~ s/\n//g;

    # build the xref object and store it
    $xref->{ACCESSION}     = $ipi_ac;
    $xref->{VERSION}       = $ipi_ver;
    $xref->{LABEL}         = $ipi;
    $xref->{DESCRIPTION}   = $description;
    $xref->{SEQUENCE}      = $sequence;
    $xref->{SOURCE_ID}     = $source_id;
    $xref->{SPECIES_ID}    = $species_id;
    $xref->{SEQUENCE_TYPE} = 'peptide';
    $xref->{STATUS}        = 'experimental';
    $xref->{INFO_TYPE}     = "SEQUENCE_MATCH";

    push @xrefs, $xref;

  }

  $ipi_io->close();


  XrefParser::BaseParser->upload_xref_object_graphs(\@xrefs);

  print scalar(@xrefs) . " IPI xrefs succesfully parsed\n" if($verbose);

  return 0; #successful
}

1;