code: func Compatible(v string) (bool, error) {
  	if len(v) < 5 {
  		return false, fmt.Errorf("invalid version string format %#v", v)
  	}
  	v = v[1:]
  	elems := strings.Split(v, ".")
  	if len(elems) != 3 {
  		return false, fmt.Errorf("version not of the form Major.Minor.Build %#v", v)
  	}
  	mj, err := strconv.Atoi(elems[0])
  	if err != nil {
  		return false, fmt.Errorf("invalid major version number %#v, must be number", elems[0])
  	}
  	return mj == Major, nil
  }
docs: // Compatible returns true if Major matches the major version of the given version string.
  // It returns an error if the given string is not a valid version string.