private fields

private_fields.py

      # Inherit private fields (like GenericForeignKey) from the parent
      # class
      for field in base._meta.private_fields:
          if field.name in field_names:
              if not base._meta.abstract:
                  raise FieldError(
                      'Local field %r in class %r clashes with field of '
                      'the same name from base class %r.' % (
                          field.name,
                          name,
                          base.__name__,
                      )
                  )
          else:
              field = copy.deepcopy(field)
              if not base._meta.abstract:
                  field.mti_inherited = True
              new_class.add_to_class(field.name, field)