.. method:: Logger.setLevel(lvl)
Sets the threshold for this logger to *lvl*. Logging messages which are less
- severe than *lvl* will be ignored. When a logger is created, the level is set to
- :const:`NOTSET` (which causes all messages to be processed when the logger is
- the root logger, or delegation to the parent when the logger is a non-root
- logger). Note that the root logger is created with level :const:`WARNING`.
+ severe than *lvl* will be ignored; logging messages which have severity *lvl*
+ or higher will be emitted by whichever handler or handlers service this logger,
+ unless a handler's level has been set to a higher severity level than *lvl*.
+
+ When a logger is created, the level is set to :const:`NOTSET` (which causes
+ all messages to be processed when the logger is the root logger, or delegation
+ to the parent when the logger is a non-root logger). Note that the root logger
+ is created with level :const:`WARNING`.
The term 'delegation to the parent' means that if a logger has a level of
NOTSET, its chain of ancestor loggers is traversed until either an ancestor with