Docusign使用PHP客户端在模板中的pdf文件上为textfield添加值

I created a template on docusign and added a pdf document to it. Next I dragged a text field and dropped it on pdf file and changed its data label to service as shown in screenshot below.

Now I want to add value in that field using php code so that recipient see that value before signing the document. Below is the code that I am using but its not working. The recipent see a blank field.

  $textTab = new \DocuSign\eSign\Model\Text();
   // match the name with data label name added on pdf.
  $textTab->setTabLabel("service");
  $textTab->setValue('developement');                    
  $tabs = new DocuSign\eSign\Model\Tabs();
  $tabs->setTextTabs(array($textTab));               
  $templateRole->setTabs($tabs);

Please help me. Thanks