[Twisted-Python] callLater

Hi. I need to implement a function for scheduling function calls at specific times. A simple implementation is: def callAt(when): from twisted.internet import reactor delta = when - datetime.now() delay = delta.days * 24 * 3600 + delta.seconds + delta.microseconds / 1000000. return reactor.callLater(delay) However I'm going to have lots of this scheduled calls, many of these are far away in the future. Can this be a problem? An alternative implementation is to use LoopingCall that, say, every 15 minutes, check the scheduled functions. Here I can think of some optimization, to avoid a linear search. Thanks Manlio Perillo