def configure_block_size(config, tokenizer):
    """
    Configures the block size for the given configuration and tokenizer.

    This function sets the `block_size` attribute in the `config` object based on the `tokenizer`'s maximum model length.
    If `config.block_size` is -1, it is set to None. If `config.block_size` is None, it defaults to the tokenizer's
    `model_max_length` but not exceeding 1024. If `config.block_size` is specified and exceeds the tokenizer's
    `model_max_length`, a warning is logged and the block size is set to the tokenizer's `model_max_length`.

    Args:
        config (object): Configuration object that contains the `block_size` attribute.
        tokenizer (object): Tokenizer object that contains the `model_max_length` attribute.

    Returns:
        object: The updated configuration object with the `block_size` attribute set.
    """
    if config.block_size == -1:
        config.block_size = None

    if config.block_size is None:
        block_size = tokenizer.model_max_length
        if block_size > 1024:
            logger.warning(
                "The chosen tokenizer supports a `model_max_length` that is longer than the default `block_size` value"
                " of 1024. If you would like to use a longer `block_size` up to `tokenizer.model_max_length` you can"
                " override this default with `--block_size xxx`."
            )
            block_size = 1024
    else:
        if config.block_size > tokenizer.model_max_length:
            logger.warning(
                f"The block_size passed ({config.block_size}) is larger than the maximum length for the model"
                f"({tokenizer.model_max_length}). Using block_size={tokenizer.model_max_length}."
            )
        block_size = min(config.block_size, tokenizer.model_max_length)

    config.block_size = block_size

    logger.info(f"Using block size {block_size}")
    return config

    Configures the block size for the given configuration and tokenizer.

    This function sets the `block_size` attribute in the `config` object based on the `tokenizer`'s maximum model length.
    If `config.block_size` is -1, it is set to None. If `config.block_size` is None, it defaults to the tokenizer's
    `model_max_length` but not exceeding 1024. If `config.block_size` is specified and exceeds the tokenizer's
    `model_max_length`, a warning is logged and the block size is set to the tokenizer's `model_max_length`.

    Args:
        config (object): Configuration object that contains the `block_size` attribute.
        tokenizer (object): Tokenizer object that contains the `model_max_length` attribute.

    Returns:
        object: The updated configuration object with the `block_size` attribute set.
    
src/autotrain/trainers/clm/utils.py