def rethrow(exception, additional_message):
    """
    Re-raise the last exception that was active in the current scope
    without losing the stacktrace but adding an additional message.
    This is hacky because it has to be compatible with both python 2/3
    """
    e = exception
    m = additional_message
    if not e.args:
        e.args = (m,)
    else:
        e.args = (e.args[0] + m,) + e.args[1:]
    raise e