@classmethod
def register_count_log2(cls, parameters_byte):
    """
        Extracts the log2(register_count) from the parameters byte of a serialized ``HLLType.FULL`` HLL.

        :param byte parameters_byte: the parameters byte of the serialized HLL
        :returns: log2(registerCount) of the serialized HLL
        :rtype: int
        """
    return parameters_byte & cls.LOG2_REGISTER_COUNT_MASK
