The Python C-API is pretty weird here. By calling PyErr_NormalizeException, we get an instance of SyntaxError (or its subclass IndentationError) as the value instead of a plain tuple, which makes things clearer.

Another effect is that we get the "Missing parentheses in call to 'print'" message when relevant instead of just "invalid syntax".

Parsing valid files still works, parsing broken files doesn't crash, and in case of python2 'print' or 'exec' statements we display the more detailed error.