def test_rangeMissingStop(self):
        """
        A single bytes range without an explicit stop position is parsed into a
        two-tuple giving the start position and L{None}.
        """
        self.assertEqual(
            self.resource._parseRangeHeader(b'bytes=0-'), [(0, None)])

        A single bytes range without an explicit stop position is parsed into a
        two-tuple giving the start position and L{None}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_static.py