How can i add empty blank rows in purchase report? and dont know if blank_line is executing perfectly. i followed this link -forum.openerp.com/forum/topic8508.html' code:

<section>
  <para style="terp_default_8">[[ repeatIn(o.order_line,'line') ]][[line_no() ]]</para>
    <blockTable colWidths="20.0,100.0,150.0,80.0,50.0,20.0,60.0,50.0" style="Table_Order_Pur_line_Content">
      <tr>[[ blank_line(10) ]]<!--[[ setTag('para','para') ]] error-->
      <td>
            <para style="terp_default_9"> </para>
          </td>
          <td>
            <para style="terp_default_9">[[ ', '.join(map(lambda x: x.name, line.taxes_id)) ]]</para>
          </td>
          <td>
            <para style="terp_default_9">[[line.name]]</para>
          </td>
          <td>
             <para style="terp_default_Right_9">[[ formatLang(line.product_qty ) ]]</para>
           </td>
          <td>
            <para style="terp_default_Right_9">[[ formatLang(line.price_unit,digits=get_digits(dp='Product Price') ) ]]</para>
           </td>
             <td>
                <para style="terp_default_Right_9"> </para>
              </td>
         <td>
                <para style="terp_default_Right_9"> </para>
              </td>
         <td>
                    <para style="terp_default_Right_9">[[ formatLang(line.price_subtotal,digits=get_digits(dp='Account'), currency_obj=o.pricelist_id.currency_id ) ]] </para>
            </td>
    </tr>
</blockTable>