XML Python Parsing Namespace

Question

I have an XML I am trying to parse:

?xml version="1.0" encoding="utf-8"?

new:SumRoot xmlns:ct="link"

xmlns:bo="link"

..new:PolarBear

....new:PolarBear

......new:PolarBearVeb

........new:Donkey>21

........new:Obj

..........bo:Boston

............bo:Number>T6663

..............bo:MarkedAsNumber /

Currently, I have:

tree = ET.parse(.xml)
root = tree.getroot()
for child in root.findall('bo:Number'):
   idea = child.find('Number').text
   print idea

And I keep getting "SyntaxError: expected path separator (:)"