code: func ListenTLS(address string, certFile, keyFile string, cipherSuites []uint16) (net.Listener, error) {
  	tlsConfig, err := CreateTLSConfiguration(certFile, keyFile, cipherSuites)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  	return tls.Listen("tcp", address, tlsConfig)
  }
docs: // ListenTLS sets up TLS listener for the http handler, starts listening
  // on a TCP socket and returns the socket which is ready to be used
  // for http.Serve