Should retrieve all collections for a given workspace. 
      Syntax
         
         
            - 
            (
            NSArray *
            ) 
            
               getCollectionsByWorkspace
            
            : 
            (
            SDMODataWorkspace *
            ) 
            workspace_in
         
      
      Parameters
         
         
            - 
               workspace_in – 
               the workspace which 'holds' collections
            
 
         
       
      Returns
         collections for the given workspace