[python-sybase] More Pythonic default args

[Skip M. <sk...@po...>]

It seems more Pythonic to use None as a default parameter value instead of
mutable objects like dictionaries and lists, even when the parameters aren't
modified by the function.  A simple patch for execute() and executemany() is
attached.

-- 
Skip Montanaro
Got gigs? http://www.musi-cal.com/submit.html
Got spam? http://www.spambayes.org/
sk...@po...