[Twisted-Python] Controlling twisted logging

Hello, Having just spent some time trying to "turn off" twisted logging via log.discardLogs() and/or log.startLogging(log.NullFile()) in a twisted app that initially logs to an actual file, it seems that log.startLogging(log.NullFile()) only works as expected if no previous startLogging call using a valid file object has been made. Otherwise, messages continue to be logged. Is this observation correct, or am I overlooking some way to enable logging to a logfile and subsequently disable it? In my above experiments, log.discardLogs() seemed to have no effect either once valid file logging had been initiated with log.startLogging. Win2K, Python 2.3.3, Twisted 1.3.0 Thanks for any info, Norm Petterson