code: def _export_to2marc(self, key, value):
      
      def _is_for_cds(value):
          return 'CDS' in value
  
      def _is_for_hal(value):
          return 'HAL' in value and value['HAL']
  
      def _is_not_for_hal(value):
          return 'HAL' in value and not value['HAL']
  
      result = []
  
      if _is_for_cds(value):
          result.append({'c': 'CDS'})
  
      if _is_for_hal(value):
          result.append({'c': 'HAL'})
      elif _is_not_for_hal(value):
          result.append({'c': 'not HAL'})
  
      return result
docs: Populate the ``595`` MARC field.