code: func GetPkgRelativePath(path string) (string, error) {
  	abspath, err := filepath.Abs(path)
  	if err != nil {
  		abspath = path
  	}
  	if strings.HasSuffix(abspath, ".go") {
  		abspath = filepath.Dir(abspath)
  	}
  	for _, base := range Gopath() {
  		projectRoot := filepath.FromSlash(fmt.Sprintf("%s/src/", base))
  		if strings.HasPrefix(abspath, projectRoot) {
  			return strings.TrimPrefix(abspath, projectRoot), nil
  		}
  	}
  	return "", errors.New("no project relative path found")
  }
docs: // GetPkgRelativePath returns the Go relative relative path derived
  // form the given path