t.i.d.D.callback(self, result) : method documentation

Run all success callbacks that have been added to this Deferred.

Each callback will have its result passed as the first argument to the next; this way, the callbacks act as a 'processing chain'. If the success-callback returns a Failure or raises an Exception, processing will continue on the *error* callback chain. If a callback (or errback) returns another Deferred, this Deferred will be chained to it (and further callbacks will not run until that Deferred has a result).