There was an error while trying to deserialize parameter

Hi - Please can you tell me how do i enter the parameter in case i want to use datadriven framework for my project. What i mean is i used
$(pIDs) in <arr:int>?</arr:int>.

But i get the error saying "There was an error while trying to deserialize parameter"

is this the correct syntax $(pIDs) for the below case or is it different.



<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:tem="http://tempuri.org/" xmlns:arr="http://schemas.microsoft.com/2003/10/Serialization/Arrays">

   <soapenv:Header/>

   <soapenv:Body>

     <tem:getpolit>

         <!--Optional:-->

         <tem:pIDs>

           <!--Zero or more repetitions:-->

           <arr:int>?</arr:int>

         </tem:pIDs>

     </tem: getpolit >

   </soapenv:Body>

</soapenv:Envelope>