This class represents an action that should be run only after a certain amount
of time has passed -- a timer. Timer is a subclass of Thread and
as such also functions as an example of creating custom threads.
Timers are started, as with threads, by calling their start() method. The
timer can be stopped (before its action has begun) by calling the
cancel() method. The interval the timer will wait before executing
its action may not be exactly the same as the interval specified by the
user.
For example:
def hello():
print "hello, world"
t = Timer(30.0, hello)
t.start() # after 30 seconds, "hello, world" will be printed