code: func CreateCertificate(principal string, certType uint32) (*ssh.Certificate, ssh.Signer, error) {
  	// Create RSA key for CA and certificate to be signed by CA.
  	caKey, err := rsa.GenerateKey(rand.Reader, teleport.RSAKeySize)
  	if err != nil {
  		return nil, nil, trace.Wrap(err)
  	}
  	key, err := rsa.GenerateKey(rand.Reader, teleport.RSAKeySize)
  	if err != nil {
  		return nil, nil, trace.Wrap(err)
  	}
  
  	cert, certSigner, err := createCertificate(principal, certType, caKey, key)
  	if err != nil {
  		return nil, nil, trace.Wrap(err)
  	}
  
  	return cert, certSigner, nil
  }
docs: // CreateCertificate creates a valid 2048-bit RSA certificate.