code: func EnsureFormatted() error {
  	cmd := exec.Command("goimports", "-e", "-d", ".")
  	var stdout, stderr bytes.Buffer
  	cmd.Stdout = &stdout
  	cmd.Stderr = &stderr
  	err := cmd.Run()
  	if err != nil {
  		return err
  	}
  	if stdout.String() != "" {
  		if mg.Verbose() {
  			log.Print(stdout.String())
  		}
  		return errors.New("`goimports -e -d .` found import errors. Run `goimports -e -w .` to fix them")
  	}
  	return nil
  }
docs: // EnsureFormatted ensures that the source code is formatted with goimports