[Traits] dirty trait metadata

Hi,

Consider the following:

-----------------
from numpy import *
from enthought.traits.api import *
class Data(HasTraits):
     x = Array
     def _x_changed(self, value):
         print value

x = linspace(0, 1)
d = Data(x=x)
-------------------

Now I'd like to always call _x_changed when the x trait is set.  Thus, 
I'd like this to work:

x *= 2
d.x = x # Should call _x_changed

Is there a simple way of doing this?  I know that I could achieve this 
if I implemented x as a Property(Array) but is there an easier way?

Thanks.
prabhu