code: def inspect_filter_calculation(self):
          
          try:
              node = self.ctx.cif_filter
              self.ctx.cif = node.outputs.cif
          except exceptions.NotExistent:
              self.report('aborting: CifFilterCalculation<{}> did not return the required cif output'.format(node.uuid))
              return self.exit_codes.ERROR_CIF_FILTER_FAILED
docs: Inspect the result of the CifFilterCalculation, verifying that it produced a CifData output node.