Issue a POST request with `content` as the body to `endpoint` and
        return the result.

def post(self, content, endpoint=''):
        '''
        Issue a POST request with `content` as the body to `endpoint` and
        return the result.
        '''
        url = self.url(endpoint)
        post_content = json.dumps(content).encode('utf-8')
        headers = {'Content-Type': 'application/json'}
        request = Request(url, post_content, headers)

        response = urlopen(request)

        return json.loads(response.read().decode('utf-8'))