What is causing "unbound method __init__() must be called with instance as first argument" from this Python code?

Question

I have this class:

from threading import Thread 
import time

class Timer(Thread): 
    def __init__(self, interval, function, *args, **kwargs): 
        Thread.__init__() 
        self.interval = interval 
        self.function = function 
        self.args = args 
        self.kwargs = kwargs 
        self.start()

    def run(self): 
        time.sleep(self.interval) 
        return self.function(*self.args, **self.kwargs)

and am calling it with this script:

    import timer 
    def hello():
        print \"hello, world
    t = timer.Timer(1.0, hello)
    t.run()

and get this error and I can't figure out why: unbound method init() must be called with instance as first argument

Answer 1

This is a frequently asked question at SO, but the answer, in brief, is that the way you call your superclass's constructor is like:

super(Timer,self).__init__()

Answer 2

You are doing:

Thread.__init__()

Use:

Thread.__init__(self)

Or, rather, use super()

Answer 3

You just need to pass 'self' as an argument to 'Thread.init'. After that, it works on my machines.