gistfile1.py

import threading

class LVar(object):
    def __init__(self):
        self.value = 0

    def get(self, threshold):
        while not self.value >= threshold:
            pass
        return

    def put(self, value):
        self.value = max(self.value, value)

l = LVar()

class Thread1(threading.Thread):
    def run(self):
        print("invoking get")
        l.get(3)
        print("get returned")

class Thread2(threading.Thread):
    def run(self):
        print("putting 1")
        l.put(1)

class Thread3(threading.Thread):
    def run(self):
        print("putting 5")
        l.put(5)

Thread1().start()
Thread2().start()
Thread3().start()