def iterative_combine_jsons(json_directory: str, output_file: str) -> None:
    """Combine jsonl files in json_directory into one big jsonl file.

    This function does not work for nested subdirectories.

    Args:
        json_directory(str): directory containing the JSONL files
        output_file(str): path to the output combined JSONL file
    """
    json_files = [f for f in os.listdir(json_directory) if f.endswith('.jsonl')]
    with open(output_file, 'w') as outfile:
        for file_name in json_files:
            with open(os.path.join(json_directory, file_name), 'r') as infile:
                for line in infile:
                    outfile.write(line)
    log.info('JSON files have been combined into a JSONL file.')
Combine jsonl files in json_directory into one big jsonl file.

    This function does not work for nested subdirectories.

    Args:
        json_directory(str): directory containing the JSONL files
        output_file(str): path to the output combined JSONL file
    
llmfoundry/command_utils/data_prep/convert_delta_to_json.py