def METHOD_NAME(self):
    if stomp is None:
        raise MissingDependencyError("stomp")
    elif stomp.__version__ < (4, 1, 8):
        raise MissingDependencyError("stomp", version="4.1.8",
                                     installed=stomp.__version__)
    self.ssl_ca_cert = self.ssl_ca_certificate
    self.ssl_cl_cert = self.ssl_client_certificate
    self.ssl_cl_cert_key = self.ssl_client_certificate_key
    # check if certificates exist
    for f in [self.ssl_ca_cert, self.ssl_cl_cert, self.ssl_cl_cert_key]:
        if not os.path.isfile(f):
            raise ValueError("Could not open file %r." % f)
    _host = [(self.server, self.port)]
    self.__conn = stomp.Connection(host_and_ports=_host, use_ssl=True,
                                   ssl_key_file=self.ssl_cl_cert_key,
                                   ssl_cert_file=self.ssl_cl_cert,
                                   ssl_ca_certs=self.ssl_ca_cert,
                                   heartbeats=(self.heartbeat,
                                               self.heartbeat))
    self.__conn.set_listener('', StompListener(self, self.__conn, self.exchange))
    connect_and_subscribe(self.__conn, self.logger, self.exchange,
                          start=stomp.__version__ < (4, 1, 20))