code: func (i *ImageService) removeImageRef(ref reference.Named) (reference.Named, error) {
  	ref = reference.TagNameOnly(ref)
  
  	// Ignore the boolean value returned, as far as we're concerned, this
  	// is an idempotent operation and it's okay if the reference didn't
  	// exist in the first place.
  	_, err := i.referenceStore.Delete(ref)
  
  	return ref, err
  }
docs: // removeImageRef attempts to parse and remove the given image reference from
  // this daemon's store of repository tag/digest references. The given
  // repositoryRef must not be an image ID but a repository name followed by an
  // optional tag or digest reference. If tag or digest is omitted, the default
  // tag is used. Returns the resolved image reference and an error.