Python 3.4.3 introduced an internal function, _PyTraceback_Add, which is quite useful when constructing Python exception objects.

I'm using it when constructing a Python Exception object from a C++ exception object, to add "fake traceback frames" that contain the line number / file name where the C++ exception has occurred.

The function is exported via Python.h, but unfortunately it seems undocumented, and must thus be considered unstable; I request to change that.