code: func ValidChecksum(address Hash, checksum Trytes) error {
  	actualChecksum, err := Checksum(address)
  	if err != nil {
  		return err
  	}
  	if checksum != actualChecksum {
  		return ErrInvalidChecksum
  	}
  	return nil
  }
docs: // ValidChecksum checks whether the given checksum corresponds to the given address.