function/method assigment

[viscroad at gmail.com]

I have a confusion when I do some practice, the code and output are as
following,

>>> def fun():
	print 'In fun()....'


>>> testfun = fun()
In fun()....
>>> print testfun
None
>>> testfun2 = fun
>>> print testfun2
<function fun at 0x00CC1270>
>>> print testfun2()
In fun()....
None
>>>

what is 'testfun'? Why it is 'None'? And print testfun2(), what is the
meaning of 'None'?

Thanks!