@staticmethod
def __cs_bit_add(l, r):
    """
        Private, static method: used by self.__gen_cs() to bitwise add the
        next unsigned short value to the checksum

        Args:
            l (unsigned short): current checksum value
            r (unsigned short): value to add to the current checksum value

        Returns:
            unsigned short: result of bitwise add of l and r
        """
    r += l
    return (r & 65535) + (r >> 16)
