code: def update_image_digest(self, image, platform, digest):
          
          image_name_tag = self._key(image)
  
          image_name = image.to_str(tag=False)
          name_digest = '{}@{}'.format(image_name, digest)
  
          image_digests = self._images_digests.setdefault(image_name_tag, {})
          image_digests[platform] = name_digest
docs: Update parent image digest for specific platform
  
          :param ImageName image: image
          :param str platform: name of the platform/arch (x86_64, ppc64le, ...)
          :param str digest: digest of the specified image (sha256:...)