def METHOD_NAME(self):
    self.update_links({
        'instance.config.externalLink.text': 'A link',
        'instance.config.externalLink.url': 'http://opentreemap.org/'
    })
    self.assertEqual(self.instance.config['externalLink.text'], 'A link')
    self.assertEqual(self.instance.config['externalLink.url'],
                     'http://opentreemap.org/')
    self.update_links({
        'instance.config.externalLink.text': 'Different text',
    })
    self.assertEqual(self.instance.config['externalLink.text'],
                     'Different text')
    self.assertEqual(self.instance.config['externalLink.url'],
                     'http://opentreemap.org/')
    self.update_links({
        'instance.config.externalLink.url': 'http://example.com/',
    })
    self.assertEqual(self.instance.config['externalLink.text'],
                     'Different text')
    self.assertEqual(self.instance.config['externalLink.url'],
                     'http://example.com/')
    self.update_links({
        'instance.config.externalLink.text': '',
        'instance.config.externalLink.url': ''
    })
    self.assertEqual(self.instance.config['externalLink.text'], '')
    self.assertEqual(self.instance.config['externalLink.url'], '')