fields.py 文件源码

def __get__(self, instance, owner):
        if instance is None:
            return self

        value = instance._data.get(self.name)

        self._auto_dereference = instance._fields[self.name]._auto_dereference
        if self._auto_dereference and isinstance(value, (dict, SON)):
            dereferenced = self.dereference(value)
            if dereferenced is None:
                raise DoesNotExist('Trying to dereference unknown document %s' % value)
            else:
                instance._data[self.name] = dereferenced

        return super(GenericReferenceField, self).__get__(instance, owner)