How i can make parentheses before a field that will be printed if it exists

[Caroline]

Hi I would like to make parentheses before a field that will be printed if it exists :

something like that : (service.gruppe.rec_name)
Here is the code :

          <table:table-cell table:style-name="Table3.MS" office:value-type="string">
             <text:p text:style-name="P5"><text:placeholder text:placeholder-type="text">&lt;service.rang&gt;</text:placeholder><text:placeholder text:placeholder-type="text">&lt;(service.gruppe.rec_name) if service.gruppe else ''&gt;</text:placeholder></text:p>
          </table:table-cell>

Although a parenthesis is placed before service.gruppe.rec_name and after service.gruppe.rec_name but no parenthesis appears , just the service.gruppe.rec_name displayed. so please how i can correctly do that , exactly How i can make the parenthesis appears only if the field exists!

[ced (Cédric Krier)]

The text of the placeholder is Python code, so parenthesis there is to group Python statements.
If you want to show you must make Python format a string which contains parenthesis like:

'(%s)' % service.gruppe.rec_name if service.gruppe.rec_name else ''