def test_fieldContentWhitespace(self):
        """
        Leading and trailing linear whitespace is stripped from the header
        value passed to the C{headerReceived} callback.
        """
        header, protocol = self._headerTestSetup()
        value = self.sep.join([b' \t ', b' bar \t', b' \t', b''])
        protocol.dataReceived(b'X-Bar:' + value)
        protocol.dataReceived(b'X-Foo:' + value)
        protocol.dataReceived(self.sep)
        self.assertEqual(header, {b'X-Foo': b'bar',
                                  b'X-Bar': b'bar'})

        Leading and trailing linear whitespace is stripped from the header
        value passed to the C{headerReceived} callback.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_newclient.py