XLSXWriter::buildRelationshipsXML PHP Method

    protected function buildRelationshipsXML()
    {
        $rels_xml = "";
        $rels_xml .= '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
        $rels_xml .= '<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">';
        $rels_xml .= '<Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/officeDocument" Target="xl/workbook.xml"/>';
        $rels_xml .= '<Relationship Id="rId2" Type="http://schemas.openxmlformats.org/package/2006/relationships/metadata/core-properties" Target="docProps/core.xml"/>';
        $rels_xml .= '<Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/extended-properties" Target="docProps/app.xml"/>';
        $rels_xml .= "\n";
        $rels_xml .= '</Relationships>';
        return $rels_xml;
    }