code: def group_shelf_fqfn(self):
          
          if self._group_shelf_fqfn is None:
              # new shelf file
              self._group_shelf_fqfn = os.path.join(
                  self.tcex.args.tc_temp_path, 'groups-{}'.format(str(uuid.uuid4()))
              )
  
              # saved shelf file
              if self.saved_groups:
                  self._group_shelf_fqfn = os.path.join(self.tcex.args.tc_temp_path, 'groups-saved')
          return self._group_shelf_fqfn
docs: Return groups shelf fully qualified filename.
  
          For testing/debugging a previous shelf file can be copied into the tc_temp_path directory
          instead of creating a new shelf file.