how can i fix this
<div style="margin-top:1.2em;margin-bottom:1.2em">
<?php echo __('Canned Response');?>:
<select id="cannedResp" name="cannedResp" class="selectpicker">
<option value="0" selected="selected">— <?php echo __('Select a canned response');?> —</option>
<?php
foreach($cannedResponses as $id =>$title) {
echo sprintf('<option value="%d">%s</option>',$id,$title);
}
?>
</select>
<label class="checkbox inline"><input type='checkbox' value='1' name="append" id="append" checked="checked"><?php echo __('Append');?></label>
</div>
when i use class="selectpicker" it response this error