def test_getAllHeadersMultipleHeaders(self):
        """
        When there are multiple values for a single request header,
        L{http.Request.getAllHeaders} returns only the last value.
        """
        req = http.Request(DummyChannel(), False)
        req.requestHeaders.setRawHeaders(b"test", [b"lemur", b"panda"])
        self.assertEqual(req.getAllHeaders(), {b"test": b"panda"})

        When there are multiple values for a single request header,
        L{http.Request.getAllHeaders} returns only the last value.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_http.py