def test_multiLine(self):
        """
        A header may be split across multiple lines.  Subsequent lines begin
        with C{" "} or C{"\\t"}.
        """
        l = self.l
        self.feedMessage(response_multiline)
        self.assertEqual(len(l), 1)
        m = l[0]
        self.assertEqual(
            m.headers['via'][0],
            "SIP/2.0/UDP server10.biloxi.com;"
            "branch=z9hG4bKnashds8;received=192.0.2.3")
        self.assertEqual(
            m.headers['via'][1],
            "SIP/2.0/UDP bigbox3.site3.atlanta.com;"
            "branch=z9hG4bK77ef4c2312983.1;received=192.0.2.2")
        self.assertEqual(
            m.headers['via'][2],
            "SIP/2.0/UDP pc33.atlanta.com;"
            "branch=z9hG4bK776asdhds ;received=192.0.2.1")

        A header may be split across multiple lines.  Subsequent lines begin
        with C{" "} or C{"\t"}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_sip.py