i am using below code..below code migrated from v10 to v13

<template id="template" xml:space="preserve">
    <t t-extend="ListView.buttons" t-name="customListView.buttons">
       <t t-jquery="button.o_list_button_add" t-operation="before">
         <!-- Sale Unit -->
            <!-- -->
            <button t-if="widget.modelName == 'account.asset.asset' and widget.options.action['xml_id'] == 'bi_property_management_extend.action_property_assets_view_from_sale'"
                    class="btn btn-primary btn-sm oe_action_buttons addMore"
                    style="width:50px;" type="button">
               <span class="fa fa-search-plus" title="Advance Search Sale Unit"/>
         </button>
            <button t-if="widget.modelName == 'account.asset.asset' and widget.options.action['xml_id'] == 'bi_property_management_extend.action_property_assets_view_from_sale'"
                    class="btn btn-primary btn-sm oe_action_refresh_buttons"
                    type="button"><span class="fa fa-refresh" style="font-size:18px" title="Refresh"/></button>

     </t>
    </t>
</template>