[IronPython] Silverlight - animation from code

[Michael Foord]

Any idea why the following code does nothing? (root is the application 
root visual - the textblock becomes visible and 'starting' is printed at 
the right time - but the fint size doesn't change as I would expect from 
the Silverlight docs.)

from System import TimeSpan
from System.Windows import Duration
from System.Windows.Controls import TextBlock
from System.Windows.Media.Animation import (
    DoubleAnimation, Storyboard
)

root.Children.Clear()
root.Resources.Clear()

t = TextBlock()
t.FontSize = 20
t.Text = 'Something Blue'
root.Children.Add(t)

sb = Storyboard()
duration = Duration(TimeSpan.FromSeconds(2))
a = DoubleAnimation()
a.Duration = duration
sb.Duration = duration
sb.Children.Add(a)

Storyboard.SetTarget(a, t)
Storyboard.SetTargetProperty(a, 'FontSize')
a.From = 20
a.To = 40

def anim(s, e):
    print 'Starting'
    sb.Begin()
   
t.MouseEnter += anim

root.Resources.Add(sb)