How to use the pathlib2.PureWindowsPath function in pathlib2

self.assertEqual(pp, P('/c'))

    def test_div(self):
        # Basically the same as joinpath()
        P = self.cls
        p = P('//a')
        pp = p / 'b'
        self.assertEqual(pp, P('//a/b'))
        pp = P('/a') / '//c'
        self.assertEqual(pp, P('//c'))
        pp = P('//a') / '/c'
        self.assertEqual(pp, P('/c'))


class PureWindowsPathTest(_BasePurePathTest, unittest.TestCase):
    cls = pathlib.PureWindowsPath

    equivalences = _BasePurePathTest.equivalences.copy()
    equivalences.update({
        'c:a': [('c:', 'a'), ('c:', 'a/'), ('/', 'c:', 'a')],
        'c:/a': [
            ('c:/', 'a'), ('c:', '/', 'a'), ('c:', '/a'),
            ('/z', 'c:/', 'a'), ('//x/y', 'c:/', 'a'),
            ],
        '//a/b/': [('//a/b',)],
        '//a/b/c': [
            ('//a/b', 'c'), ('//a/b/', 'c'),
            ],
    })

    def test_str(self):
        p = self.cls('a/b/c')

def test_different_flavours_unordered(self):
        p = pathlib.PurePosixPath('a')
        q = pathlib.PureWindowsPath('a')
        with self.assertRaises(TypeError):
            p < q
        with self.assertRaises(TypeError):
            p <= q
        with self.assertRaises(TypeError):
            p > q
        with self.assertRaises(TypeError):
            p >= q

def test_concrete_class(self):
        p = self.cls('a')
        self.assertIs(
            type(p),
            pathlib.PureWindowsPath
            if os.name == 'nt' else pathlib.PurePosixPath)

def test_different_flavours_unequal(self):
        p = pathlib.PurePosixPath('a')
        q = pathlib.PureWindowsPath('a')
        self.assertNotEqual(p, q)

def path2unix(path, nojoin=False, fromwinpath=False):
    '''From a path given in any format, converts to posix path format
    fromwinpath=True forces the input path to be recognized as a Windows path (useful on Unix machines to unit test Windows paths)'''
    if fromwinpath:
        pathparts = list(PureWindowsPath(path).parts)
    else:
        pathparts = list(PurePath(path).parts)
    if nojoin:
        return pathparts
    else:
        return posixpath.join(*pathparts)