code: func TLSCertHash(config fab.EndpointConfig) ([]byte, error) {
  	certs := config.TLSClientCerts()
  	if len(certs) == 0 {
  		return computeHash([]byte(""))
  	}
  
  	cert := certs[0]
  	if len(cert.Certificate) == 0 {
  		return computeHash([]byte(""))
  	}
  
  	return computeHash(cert.Certificate[0])
  }
docs: // TLSCertHash is a utility method to calculate the SHA256 hash of the configured certificate (for usage in channel headers)