code: func IsCompressedPubKey(pubKey []byte) bool {
  	// The public key is only compressed if it is the correct length and
  	// the format (first byte) is one of the compressed pubkey values.
  	return len(pubKey) == PubKeyBytesLenCompressed &&
  		(pubKey[0]&^byte(0x1) == pubkeyCompressed)
  }
docs: // IsCompressedPubKey returns true the the passed serialized public key has
  // been encoded in compressed format, and false otherwise.