What is the best way to clear threading._timer threads in Python?

Question

So, I have these two classes that I use to schedule functions in a timer. They work very well, but they will run in the program for very long periods of time, so I want to make sure that I clean the threads that “stop” correctly.

Can someone explain how I cleared these threads from threading._Timer since I use the setDaemon (True) flag.

How I will use these classes: I will create a class manager object and keep calling MyClassManager.add_oneTimeOperation (MyFunction, 5) over and over again ...

Thank!

class Operation(threading._Timer):
    alive = True

    def __init__(self, *args, **kwargs):
        threading._Timer.__init__(self, *args, **kwargs)
        self.setDaemon(True)

    def run(self):
        while (self.alive):
            self.finished.clear()
            self.finished.wait(self.interval)
            if not self.finished.isSet():
                self.function(*self.args, **self.kwargs)
            else:
                return
            #self.finished.set()

    def run_once(self):
        self.finished.clear()
        self.finished.wait(self.interval)
        if not self.finished.isSet():
            self.function(*self.args, **self.kwargs)
        else:
            return
        self.finished.set()

    def cancel(self):
        self.finished.set()
        self.alive = False

class Manager(object):

    ops = []

    def add_operation(self, operation, interval, args=[], kwargs={}):
        op = Operation(interval, operation, args, kwargs)
        self.ops.append(op)
        thread.start_new_thread(op.run, ())

    def add_oneTimeOperation(self, operation, interval, args=[], kwargs={}):
        op = Operation(interval, operation, args, kwargs)
        self.ops.append(op)
        thread.start_new_thread(op.run_once, ())

    def stop(self):
        for op in self.ops:
            op.cancel()

    def clear_operations(self):
        del self.ops[:]