How to use the ansi2html.converter.ANSI_NEGATIVE_OFF function in ansi2html

def test_inverse_text(self):
        sample = 'NORMAL\x1b[%dmINVERSE\x1b[%dmNORMAL\x1b[0m' % (ANSI_NEGATIVE_ON, ANSI_NEGATIVE_OFF)
        html = Ansi2HTMLConverter(inline=False).convert(sample, full=False)
        expected = six.u('NORMAL<span class="inv_background inv_foreground">INVERSE</span>NORMAL')
        self.assertEqual(expected, html)

        sample = 'NORMAL\x1b[%dm303030\x1b[%dm!30!30!30\x1b[%dm303030\x1b[0m' % (30, ANSI_NEGATIVE_ON, ANSI_NEGATIVE_OFF)
        html = Ansi2HTMLConverter(inline=False).convert(sample, full=False)
        expected = six.u('NORMAL<span class="ansi30">303030</span><span class="inv30 inv_foreground">!30!30!30</span><span class="ansi30">303030</span>')
        self.assertEqual(expected, html)

        sample = 'NORMAL\x1b[%dm313131\x1b[%dm!31!31!31\x1b[%dm!31!43\x1b[%dm31+43\x1b[0mNORMAL' % (31, ANSI_NEGATIVE_ON, 43, ANSI_NEGATIVE_OFF)
        html = Ansi2HTMLConverter(inline=False).convert(sample, full=False)
        expected = six.u('NORMAL<span class="ansi31">313131</span><span class="inv31 inv_foreground">!31!31!31</span><span class="inv31 inv43">!31!43</span><span class="ansi31 ansi43">31+43</span>NORMAL')
        self.assertEqual(expected, html)