keys/hd/address.go
func HexDecode(str string) []byte {
	b, _ := hex.DecodeString(str)
	return b
}
func HexDecode(str string) []byte {
	b, _ := hex.DecodeString(str)
	return b
}
// HexDecode hex decodes the str. If str is not valid hex
// it will return an empty byte slice.