code: func (e *Engine) ImagePull(ctx context.Context, ref string, all bool) (io.ReadCloser, error) {
  	auth, err := makeEncodedAuthConfigFromRemote(e.config.Docker.AuthConfigs, ref)
  	if err != nil {
  		return nil, err
  	}
  	pullOptions := dockertypes.ImagePullOptions{All: all, RegistryAuth: auth}
  	return e.client.ImagePull(ctx, ref, pullOptions)
  }
docs: // ImagePull pull Image