code: def export_deleted_fields(self):
          
          result = []
          if self.__modified_data__ is not None:
              return result
  
          for index, item in enumerate(self):
              try:
                  deleted_fields = item.export_deleted_fields()
                  result.extend(['{}.{}'.format(index, key) for key in deleted_fields])
              except AttributeError:
                  pass
          return result
docs: Returns a list with any deleted fields form original data.
          In tree models, deleted fields on children will be appended.