code: func (c *TrustedCerts) SSHCertPublicKeys() ([]ssh.PublicKey, error) {
  	out := make([]ssh.PublicKey, 0, len(c.HostCertificates))
  	for _, keyBytes := range c.HostCertificates {
  		publicKey, _, _, _, err := ssh.ParseAuthorizedKey(keyBytes)
  		if err != nil {
  			return nil, trace.Wrap(err)
  		}
  		out = append(out, publicKey)
  	}
  	return out, nil
  }
docs: // SSHCertPublicKeys returns a list of trusted host SSH certificate authority public keys