import logging

FORMAT = '[%(asctime)-15s] [%(levelname)s:%(lineno)d] %(message)s'
logging.basicConfig(format=FORMAT, level=logging.INFO)
logger = logging.getLogger('example')

logger.debug("This is a debug message what won't be seen with level=logging.INFO")
logger.info("This is an info message that will be seen")
logger.error("This is an error message that will be seen")
logger.critical("This is a critical message that will be seen")

try:
    foo
except Exception, ex:
    logger.exception("This is an exception log")
    
logger.setLevel(logging.DEBUG)
logger.debug('Now you can see debug messages')