You're right, I was confused by the statement "arg is not a Python 
function". I didn't realize 'arg' meant the function I passed to 
getargspec, I thought it was just strange.

After digging a bit into inspect.py, may I suggest line 814 be changed 
from:
raise TypeError('arg is not a Python function')

to:
raise TypeError('%s is not a Python function' % func)

That way the error I would have received would have given:
TypeError: <built-in function print> is not a Python function