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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def authenticate(self, user, password):
 """ Method to get simplenote auth token Arguments: - user (string):
 simplenote email address - password (string):
 simplenote password Returns: Simplenote API token as string """


        request = Request(AUTH_URL)
        request.add_header('X-Simperium-API-Key', API_KEY)
        if sys.version_info < (3, 3):
            request.add_data(json.dumps({'username': user, 'password': password}))
        else:
            request.data = json.dumps({'username': user, 'password': password}).encode()
        try:
            res = urllib2.urlopen(request).read()
            token = json.loads(res.decode('utf-8'))["access_token"]
        except HTTPError:
            raise SimplenoteLoginFailed('Login to Simplenote API failed!')
        except IOError: # no connection exception
            token = None
        return token