code: func CertificateRequestFromFile(file string) (*x509.CertificateRequest, error) {
  	pemBlock, err := ioutil.ReadFile(file)
  	if err != nil {
  		return nil, errors.Wrap(err, "failed to read file")
  	}
  
  	csr, err := parseCSRPEM(pemBlock)
  	if err != nil {
  		return nil, errors.Wrapf(err, "error reading certificate request file %s", file)
  	}
  	return csr, nil
  }
docs: // CertificateRequestFromFile returns the CertificateRequest from a given PEM-encoded file.
  // Returns an error if the file could not be read or if the CSR could not be parsed.