code: func (k SigningPublicKey) Verify(msg []byte, sig []byte) error {
  	ok := ed25519.Verify(k[:], msg, sig)
  	if !ok {
  		return saltpack.ErrBadSignature
  	}
  	return nil
  }
docs: // Verify runs the NaCl verification routine on the given msg / sig
  // input.