python thread error
Question: 
    obj = functioning()
    
    from threading import Thread
    Thread(target=obj.runCron(cronDetails)).start()
    print "new thread started..."
    

I am runnning this, this should run as new thread for runCron function and
should print new thread started. but this is not printing new thread started
and not creating new thread


Answer: You question is missing some details, e.g. what error message you are getting,
etc. – below is a working example mimicked after your code.

    
    
    #!/usr/bin/env python
    
    import time
    
    class Obj(object):
        def runCron(self, cronDetails):
            time.sleep(1)
            print cronDetails
    
    obj = Obj()
    cronDetails = "I'm here."
    
    from threading import Thread
    
    # Note, that the `target` is a function object
    # (or a callable in general), we don't actually call it yet!
    t = Thread(target=obj.runCron, args=(cronDetails, ))
    t.start()
    print "New thread started (should be here in a second) ..."
    

It prints:

    
    
    New thread started (should be here in a second) ...
    I'm here.
    

