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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 _send_features(self, features):
 """ Send a query to the backend api with a list of observed features in this log file :param features: Features found in the log file :return: Response text from ThreshingFloor API """


        # Hit the auth endpoint with a list of features
        try:
            r = requests.post(self.base_uri + self.api_endpoint, json=features, headers={'x-api-key': self.api_key})
        except requests.exceptions.ConnectionError:
            raise TFAPIUnavailable("The ThreshingFloor API appears to be unavailable.")

        if r.status_code != 200:
            sys.stderr.write("%s\n" % r.text)
            raise TFAPIUnavailable("Request failed and returned a status of: {STATUS_CODE}"
                                   .format(STATUS_CODE=r.status_code))

        return json.loads(r.text)