How to use the dictdiffer.utils.dot_lookup function in dictdiffer

def test_dot_lookup(self):
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b'), 'hello')
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ['a', 'b']),
                         'hello')

        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b', parent=True),
                         {'b': 'hello'})
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ''),
                         {'a': {'b': 'hello'}})

def test_dot_lookup(self):
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b'), 'hello')
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ['a', 'b']),
                         'hello')

        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b', parent=True),
                         {'b': 'hello'})
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ''),
                         {'a': {'b': 'hello'}})

def test_dot_lookup(self):
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b'), 'hello')
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ['a', 'b']),
                         'hello')

        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b', parent=True),
                         {'b': 'hello'})
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ''),
                         {'a': {'b': 'hello'}})

def test_dot_lookup(self):
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b'), 'hello')
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ['a', 'b']),
                         'hello')

        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, 'a.b', parent=True),
                         {'b': 'hello'})
        self.assertEqual(dot_lookup({'a': {'b': 'hello'}}, ''),
                         {'a': {'b': 'hello'}})

def change(node, changes):
        dest = dot_lookup(destination, node, parent=True)
        if isinstance(node, string_types):
            last_node = node.split('.')[-1]
        else:
            last_node = node[-1]
        if isinstance(dest, LIST_TYPES):
            last_node = int(last_node)
        _, value = changes
        dest[last_node] = value

def remove(node, changes):
        for key, value in changes:
            dest = dot_lookup(destination, node)
            if isinstance(dest, SET_TYPES):
                dest -= value
            else:
                del dest[key]

def add(node, changes):
        for key, value in changes:
            dest = dot_lookup(destination, node)
            if isinstance(dest, LIST_TYPES):
                dest.insert(key, value)
            elif isinstance(dest, SET_TYPES):
                dest |= value
            else:
                dest[key] = value