Thanks everyone; it has been very educational. > Dave Angel: > ...we'll find that two of the alternatives are not even equivalent.
That helped me realize (a,b) != (None, None) is not correct for the function. It's a case where two parameters have None as the default argument. What I want is to make sure that both are not None. I am now considering: if None not in (a,b): or if (a is not None) and (b is not None): -- https://mail.python.org/mailman/listinfo/python-list
