'Internal function. It reports exception on sys.stderr.'

def report_callback_exception(self, exc, val, tb):

    import traceback
    import sys
    sys.stderr.write('Exception    in    Tkinter    callback\n')
    sys.last_type = exc
    sys.last_value = val
    sys.last_traceback = tb
    traceback.print_exception(exc, val, tb)
