Why no output from xml.dom.ext.PrettyPrint?

[kj]

OK, the following should work but doesn't, and I can't figure out
why:

>>> from xml.marshal.generic import dumps
>>> dumps( ( 1, 2.0, 'foo', [3,4,5] ) )
'<?xml version="1.0"?><marshal><tuple><int>1</int><float>2.0</float><string>foo</string><list id="i2"><int>3</int><int>4</int><int>5</int></list></tuple></marshal>'
>>> from xml.dom.ext import PrettyPrint
>>> PrettyPrint( dumps( ( 1, 2.0, 'foo', [3,4,5] ) ) )
>>> import sys
>>> PrettyPrint( dumps( ( 1, 2.0, 'foo', [3,4,5] ) ), sys.stdout )
>>> 

Why am I seeing no output from PrettyPrint?

TIA!

kynn

-- 
NOTE: In my address everything before the first period is backwards;
and the last period, and everything after it, should be discarded.