code: func ValidAddress(address Hash) error {
  	switch len(address) {
  	case 90:
  		if err := ValidChecksum(address[:81], address[81:]); err != nil {
  			return err
  		}
  	case 81:
  	default:
  		return ErrInvalidAddress
  	}
  	return ValidTrytes(address)
  }
docs: // ValidAddress checks whether the given address is valid.