docs: def check_trajectory_id(self, dataset):
          '''
          Checks that if a variable exists for the trajectory id it has the appropriate attributes
  
          :param netCDF4.Dataset dataset: An open netCDF dataset
          '''
          results = []
          exists_ctx = TestCtx(BaseCheck.MEDIUM, 'Variable defining "trajectory_id" exists')
          trajectory_ids = dataset.get_variables_by_attributes(cf_role='trajectory_id')
          # No need to check
          exists_ctx.assert_true(trajectory_ids, 'variable defining cf_role="trajectory_id" exists')
          if not trajectory_ids:
              return exists_ctx.to_result()
          results.append(exists_ctx.to_result())
          test_ctx = TestCtx(BaseCheck.MEDIUM, 'Recommended attributes for the {} variable'.format(trajectory_ids[0].name))
          test_ctx.assert_true(
              getattr(trajectory_ids[0], 'long_name', '') != "",
              "long_name attribute should exist and not be empty"
          )
          results.append(test_ctx.to_result())
          return results