i'm trying to customized report_purchasequotation.xml and report_purchaseorder.xml. I have added a new th to add Product reference at the supplier in my reports. My problem is when i use span t-field="order_line.product_id.product_code" (field product_code in the model product.supplierinfo ) it shows error QWebException: 'product_code'. Any help please ?

<table class="table table-condensed">
            <thead>
                <tr>
                    <th><strong>Article</strong></th>
                    <th><strong>Référence fournisseur</strong></th>
                    <th><strong>Désignation</strong></th>
                    <th class="text-center"><strong>Expected Date</strong></th>
                    <th class="text-right"><strong>Qty</strong></th>
                </tr>
            </thead>
            <tbody>
                <tr t-foreach="o.order_line" t-as="order_line">
                    <td>
                        <span t-field="order_line.name"/>
                    </td>

                    <td>
                        <span t-field="order_line.product_id.product_code"/>
                    </td>
                    <td>

                    </td>

                    <td class="text-center">
                        <span t-field="order_line.date_planned"/>
                    </td>
                    <td class="text-right">
                        <span t-field="order_line.product_qty"/>
                        <span t-field="order_line.product_uom" groups="product.group_uom"/>
                    </td>
                </tr>
            </tbody>
        </table>