docs: def migrate_data(self, data, from_state):
          """Migrate data objects.
  
          :param data: Queryset containing all data objects that need
              to be migrated
          :param from_state: Database model state
          """
          for instance in data:
              if instance.status == 'ER':
                  continue
  
              container = getattr(instance, self.schema_type, {})
              schema = container.pop(self.field[-1])
              container[self.new_field] = schema
  
              setattr(instance, self.schema_type, container)
              instance.save()