code: func NewDockerFromString(ds string) (Distribution, error) {
  	urlStr := NewCIMDString(TypeDocker, distDockerVersion, ds)
  	u, err := url.Parse(urlStr)
  	if err != nil {
  		return nil, err
  	}
  	return NewDocker(u)
  }
docs: // NewDockerFromDockerString creates a new docker distribution from the provided
  // docker string (like "busybox", "busybox:1.0", "myregistry.example.com:4000/busybox" etc...)