Hello Community ,I'm facing a probleme ,i want to create an picking wich show the list of product sales grouped by gamme and product

i do this :

<tbody>
   <t t-set="product" t-value="[]" />
   <t t-foreach="o.move_lines" t-as="move">
      <t t-set="product" t-value="product+[move.product_id.id]" />
   </t>
   <t t-set="product_gamme" t-value="[]" />
   <t t-foreach="o.move_lines" t-as="move">
      <t t-set="product_gamme" t-value="product_gamme+[move.product_id.product_gamme_id.id]"/>
   </t>

   <tr t-foreach="set(product)" t-as="prod" style="font-size: 11px;">
      <t t-set="product_code" t-value="0" />
      <t t-set="product_name" t-value="0" />
      <t t-set="qty_gr" t-value="0" />
      <t t-set="qty" t-value="0" />
      <t t-set="total" t-value="0"/>


      <t t-foreach="o.move_lines" t-as="move">
         <t t-if="prod==move.product_id.id">

t t-set="product_code" t-value="move.product_id.code" />
            <t t-set="product_name" t-value="move.product_id.name" />
            <t t-if="move.gratuite">
               <t t-set="qty_gr" t-value="qty_gr+round(move.product_uom_qty,2)" />
            </t>
            <t t-if="move.gratuite == False">
            <t t-set="qty" t-value="qty+round(move.product_uom_qty,2)" />
            </t>
            <t t-set="total" t-value="qty_gr+qty" />


         </t>
      </t>