I think that functionality of threading.Timer class can be easily extended to generate the sequence of runs with specified period. The idea comes from the GLib.timeout_add function. 

Run method of threading.Timer should look like:

    def run(self):
        """Continue execution after wait till function returns True"""
        while(not self.finished.wait(self.interval)):
            if not self.function(*self.args, **self.kwargs):
                break
        self.finished.set()