django TypeError: __str__ returned non-string (type ImageFieldFile)

原因：在model中的返回值出錯

class ContentImage(BaseModel):
    image = ImageRestrictedField()

    class Meta:
        verbose_name = 圖片'
        verbose_name_plural = verbose_name
        db_table = 't_content_image'
    
    def __str__(self):
        return self.image

把下面的隱藏掉，即可解決

 def __str__(self):
        return self.image