HW25P_hrm.py

def heart_rate_data(self):
        self.hr_countdown = None
        try:
            service, = [s for s in self.getServices() if s.uuid == self.hrmid]
            _ = service.getCharacteristics(forUUID=str(self.hrmmid))

            desc = self.getDescriptors(service.hndStart, service.hndEnd)
            d, = [d for d in desc if d.uuid == self.cccid]

            self.writeCharacteristic(d.handle, b'\x01\x00')

            def print_hr(cHandle, data):
                self.hr_countdown = time.perf_counter()
                self._log.info(data[1])

            self.delegate.handleNotification = print_hr
            self._log.info("Waiting for Heart Rate notification ...")

            while True:
                try:
                    if self.hr_countdown and (time.perf_counter() - self.hr_countdown) >= 3:
                        self._log.info("HRM completed")
                        break
                    else:
                        self.waitForNotifications(3.)

                except KeyboardInterrupt:
                    self._log.info("HRM operation closed by user")
                    self.writeCharacteristic(d.handle, b'\x00\x00')
                    break

        except BTLEException as btlE:
            self._log.error(f"{btlE}")