two labels in the window but in diferent time

[rrosa at usp.br]

Hi there,
I am trying to create a window that appears one label1="First Message" and after
of 3,4 seconds I would like to append another label in the same window
label2="Second Message" bellow of the first label, but I can only show both
labels in the same time, and not in diferent time in the same window, someone
knows something about??? 
Gratefully!

----> my code:
from anygui import *
import win32api


# Make components here
app = Application()
# Add components to the Window
w = Window()
w.set(title='Hello, again', size=(300,200))
lab = Label(text='Hello, again!', position=(10,10))
lab1 = Label(text='Hello, again!', position=(10,40))

app.add(w)
w.add(lab)
win32api.Sleep(2000)
w.add(lab1)
app.run()