Notebook has python 3.x-specific code

[hughesadam87]

Hi,

Thanks for putting this library together! I'm really enjoying learning about reactive extensions.

One issue I've encountered is that some of the examples (for example ironpython) have Python 2.x print statments. EG:

print "x y z"

So will not run in Python 3.x. However, the notebook tutorial has statements like:

xs = d.subscribe(print)

Which only works in Python 3.x. How would one subscribe the print function in Python 2.x?