@gidden can you explain the leading dunder (double underscore)?  That notation is typically reserved for compiler or language specific variables, such as `__cplusplus`.  Furthermore function access is not indicated with leading underscores like in other languages (C, Python, etc) where access is by convention.  If you wanted to indicate privacy it would be with a trailing underscore, like for member variables `Foo_`.  However, there is nothing similar to this in the GCSG for member functions.  I think this name needs to be changed to either `VerifyResponder()` or `VerifyResponder_()`.  The first one is more correct.