def standard_block(self, bytes_):
        """Adds a standard block of bytes. For TAP files, it's just the
        Low + Hi byte plus the content (here, the bytes plus the checksum)
        """
        self.out(self.LH(len(bytes_) + 1))  # + 1 for CHECKSUM byte

        checksum = 0
        for i in bytes_:
            checksum ^= (int(i) & 0xFF)
            self.out(i)

        self.out(checksum)