code: func loadCABundle(cafile string) (*x509.CertPool, error) {
  	var pem []byte
  	var err error
  
  	if cafile == "" {
  		pem, err = data.Asset("data/ca_bundle.pem")
  	} else {
  		pem, err = ioutil.ReadFile(cafile)
  
  	}
  	if err != nil {
  		return nil, fmt.Errorf("unable to find CA bundle")
  	}
  
  	c := x509.NewCertPool()
  	ok := c.AppendCertsFromPEM(pem)
  	if !ok {
  		return nil, fmt.Errorf("unable to load CA bundle from %s", cafile)
  	}
  
  	return c, nil
  }
docs: // Load CABundle creates a new CertPool from the given filename