If you specify a handler such as a RotatingFileHandler
and the path you provide in the args specification
('option') is bad, config.fileConfig() catches the
exception and 'swallows' it. The result is later on,
when that handler is specified for a logger, you get an
exception saying there is no such handler. A much
friendlier behavior would be for fileConfig() to raise
an exception so the real cause of the problem can be
easily identified. Also, if there is a bug in the code
itself, it would also get swallowed in similar fashion.
In general, silently swallowing exceptions is rarely
the best choice IMHO.

Example ini with bad path (assuming /bad/path does not
exist):
[handler_defaultrotatingfile]
class=handlers.RotatingFileHandler
args=("/bad/path/logdir/my_log.log", 'w', 100000, 10)
formatter=std