How to use the pyfcm.errors.AuthenticationError function in pyfcm

def __init__(self, api_key=None, proxy_dict=None, env=None, json_encoder=None, adapter=None):
        if api_key:
            self._FCM_API_KEY = api_key
        elif os.getenv('FCM_API_KEY', None):
            self._FCM_API_KEY = os.getenv('FCM_API_KEY', None)
        else:
            raise AuthenticationError("Please provide the api_key in the google-services.json file")

        self.FCM_REQ_PROXIES = None
        self.requests_session = requests.Session()
        retries = Retry(backoff_factor=1, status_forcelist=[502, 503],
                        method_whitelist=(Retry.DEFAULT_METHOD_WHITELIST | frozenset(['POST'])))
        self.requests_session.mount('http://', adapter or HTTPAdapter(max_retries=retries))
        self.requests_session.mount('https://', adapter or HTTPAdapter(max_retries=retries))
        self.requests_session.headers.update(self.request_headers())
        self.requests_session.mount(self.INFO_END_POINT, HTTPAdapter(max_retries=self.INFO_RETRIES))

        if proxy_dict and isinstance(proxy_dict, dict) and (('http' in proxy_dict) or ('https' in proxy_dict)):
            self.FCM_REQ_PROXIES = proxy_dict
            self.requests_session.proxies.update(proxy_dict)
        self.send_request_responses = []

        if env == 'app_engine':

failure = parsed_response.get('failure', 0)
                    canonical_ids = parsed_response.get('canonical_ids', 0)
                    results = parsed_response.get('results', [])
                    message_id = parsed_response.get('message_id', None)  # for topic messages
                    if message_id:
                        success = 1
                    if multicast_id:
                        response_dict['multicast_ids'].append(multicast_id)
                    response_dict['success'] += success
                    response_dict['failure'] += failure
                    response_dict['canonical_ids'] += canonical_ids
                    response_dict['results'].extend(results)
                    response_dict['topic_message_id'] = message_id

            elif response.status_code == 401:
                raise AuthenticationError("There was an error authenticating the sender account")
            elif response.status_code == 400:
                raise InvalidDataError(response.text)
            elif response.status_code == 404:
                raise FCMNotRegisteredError("Token not registered")
            else:
                raise FCMServerError("FCM server is temporarily unavailable")
        return response_dict

def send_request(self, payloads=None):
        for payload in payloads:
            request = HTTPRequest(
                url=self.FCM_END_POINT,
                method='POST',
                headers=self.request_headers(),
                body=payload
            )

            response = yield self.http_client.fetch(request)

            if response.code == 200:
                yield self.parse_response(response)
                return
            elif response.code == 401:
                raise AuthenticationError('There was an error authenticating the sender account')
            elif response.code == 400:
                raise InternalPackageError('Unknown internal error')
            else:
                raise FCMServerError('FCM server is temporarily unavailable')