Find records for value in Multi Select lookup

Find records for value in Multi Select lookup

Hi There

We have a form (Case_Details) which has a Multi Select lookup to another form (Client)

On saving a new Case_Details form we want to find any other cases that relate to any of the selected Clients on this new case.

I have the following deluge script and the line highlighted bold is not valid for some reason

  1. clients = Client[ID in input.Client_Names];
    email_body="";
    for each c in clients
    {
          //find any other cases which are for the selected client
    matches = (Case_Details[Client_Names.contains(c.ID) && Case_Code != input.Case_Code]);
    for each m in matches
    {
                //do some other things
    }
    }

The field "Client_Names" says it is a longlist in the Refer Fields popout.

Can you please help us work out what that line should be?  I want matches to be a list of Case_Details for the Client c

Thanks
Marcus