registerForPushNotificationsAsync = async () => {
    if (Constants.isDevice) {
      const { status: existingStatus } = await Permissions.getAsync(Permissions.NOTIFICATIONS);
      let finalStatus = existingStatus;

      if (existingStatus !== 'granted') {
        const { status } = await Permissions.askAsync(Permissions.NOTIFICATIONS);
        finalStatus = status;
      }

      if (finalStatus !== 'granted') {
        alert('Failed to get push token for push notification!');
        return;
      }
      token = await Notifications.getExpoPushTokenAsync();
      console.log(`token: ${token}`);
      this.setState({ expoPushToken: token });
    } else {
      alert('Must use physical device for Push Notifications');
    }
    alert(token)
    if (Platform.OS === 'android') {
      Notifications.createChannelAndroidAsync('default', {
        name: 'default',
        sound: true,
        priority: 'max',
        vibrate: [0, 250, 250, 250],
      });
    }
  };