How to use the approvaltests.core.namer.StackFrameNamer function in approvaltests

def get_default_namer(extension=None):
    return StackFrameNamer(extension)

def test_method(self):
        n = StackFrameNamer()
        self.assertEqual("test_method", n.get_method_name())

def setUp(self):
        self.namer = StackFrameNamer()

def test_basename(self):
        n = StackFrameNamer()
        self.assertTrue(n.get_basename().endswith("NamerTests.test_basename"), n.get_basename())