scope question

[Mark Robinson]

Can anyone explain the following behaviour to me

if I type:

count = 0
def function():
	print count

function()


that works fine, however, if I type this:

count = 0
def function():
	count += 1
	print count

function()

I get the following exception

UnboundLocalError: local variable 'count' referenced before assignment

why does it find the global variable in the first case and not in the 
second?

blobby