Duplicated log lines using Python in AWS Lambda

The short version: logname = ‘processing’ formatter = logging.Formatter(fmt=’%(asctime)s %(levelname)-8s %(message)s’, datefmt=’%Y-%m-%d %H:%M:%S’) handler = logging.StreamHandler() handler.setFormatter(formatter) logger = logging.getLogger(logname) logger.setLevel(logging.DEBUG) logger.handlers = []        # === Make sure to add this line logger.addHandler(handler) logger.propagate = False    # === and this line For details, check out this link