https://sourceforge.net/p/roundup/code/ci/36630a062fb5 introduced a check 
that uses inspect.getargspec().  In our instance we were using a callable 
instance for a check ( https://hg.python.org/tracker/python-
dev/file/545a7d7ef9e4/schema.py#l251 ) and while updating roundup we got 
the failure "TypeError: <__builtin__.may_view_spam instance at 
0x7f2ac7629bd8> is not a Python function" since getargspec() only works 
with Python functions and not arbitrary callables.

We fixed this on our end by replacing the callable class with a function 
that uses a closure to store the klassname, but the fact that arbitrary 
callables are no longer supported is technically a backward incompatible 
change that you might want to fix in Roundup.

FWIW getargspec(inst.__call__) works, but there might be better way to 
fix it.