quick & dirty example of logging in a single module. You could do similar things across all modules.

sample_logging.py

import logging

logger = logging.getLogger(__name__)
logging.basicConfig(level=logging.DEBUG, filename="temp.log")
# ^^^ the filename param says print all log in a specified file.


def main():
    logger.info("Getting Started")

    for i in range(10):
        logger.debug("processing {}".format(i))
        if i == 7:
            logger.warning("HEY, there's a 7")


    items = []
    try:
        print(items[123])
    except IndexError as e:
        logger.error(e)

    logger.info("Done")


if __name__ == "__main__":
    main()