Traceback (most recent call last):

      File "/vpp/test/test_span.py", line 27, in setUpClass

        super(TestSpan, cls).setUpClass()

      File "/vpp/test/framework.py", line 411, in setUpClass

        cls.reporter.send_keep_alive(cls, 'setUpClass')

      File "/vpp/test/framework.py", line 172, in send_keep_alive

        if self.pipe is None:

      File "/vpp/test/framework.py", line 160, in pipe

        return self._pipe

    AttributeError: 'KeepAliveReporter' object has no attribute '_pipe'