notify.py

I'm trying to refactor some of my code to use the "new" method of doing 
a LISTEN on the database, I'm stuck on this key piece of code:

print "Waiting for 'NOTIFY test'"
while 1:
    if select.select([curs],[],[],5)==([],[],[]):
        print "Timeout"
    else:
        if curs.isready():
            print "Got NOTIFY: %s" % str(curs.connection.notifies.pop())


I understand the 'select' part.

What does curs.isready() do? What happens if it comes back as not True?

Also, I presume the '.pop()' ought to be called repeatedly until there 
are no more? How does one know that?

Does this all replace the previous way of doing things that looked 
something like this?

    n = curs.notifies()[0][0]  # Get the notification

Any help/explanation appreciated.

Thanks,
Michael