The logging module provides a standard interface for outputting information from a running application.

The logging library takes a modular approach and offers the several categories of components: loggers, handlers, filters, and formatters.

Logger objects have a threefold job. First, they expose several methods to application code so that applications can log messages at runtime.Second, logger objects determine which log messages to act upon based upon severity (the default filtering facility) or filter objects. Third, logger objects pass along relevant log messages to all interested log handlers.

Reference:
>> Python Standard Logging