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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def __update_throughput(table_name, key_name, read_units, write_units):
 """ Update throughput on the DynamoDB table :type table_name: str :param table_name: Name of the DynamoDB table :type key_name: str :param key_name: Configuration option key name :type read_units: int :param read_units: New read unit provisioning :type write_units: int :param write_units: New write unit provisioning """

    try:
        current_ru = dynamodb.get_provisioned_table_read_units(table_name)
        current_wu = dynamodb.get_provisioned_table_write_units(table_name)
    except JSONResponseError:
        raise

    # Check table status
    try:
        table_status = dynamodb.get_table_status(table_name)
    except JSONResponseError:
        raise
    logger.debug('{0} - Table status is {1}'.format(table_name, table_status))
    if table_status != 'ACTIVE':
        logger.warning(
            '{0} - Not performing throughput changes when table '
            'is {1}'.format(table_name, table_status))
        return

    # If this setting is True, we will only scale down when
    # BOTH reads AND writes are low
    if get_table_option(key_name, 'always_decrease_rw_together'):
        read_units, write_units = __calculate_always_decrease_rw_values(
            table_name,
            read_units,
            current_ru,
            write_units,
            current_wu)

        if read_units == current_ru and write_units == current_wu:
            logger.info('{0} - No changes to perform'.format(table_name))
            return

    dynamodb.update_table_provisioning(
        table_name,
        key_name,
        int(read_units),
        int(write_units))