code: func (p *PublicKey) SerializeCompressed() []byte {
  	b := make([]byte, 0, PubKeyBytesLenCompressed)
  	format := pubkeyCompressed
  	if isOdd(p.Y) {
  		format |= 0x1
  	}
  	b = append(b, format)
  	return paddedAppend(32, b, p.X.Bytes())
  }
docs: // SerializeCompressed serializes a public key in a 33-byte compressed format.