Flutter Health Steps Data, Datatype possibly throwing an error that makes UI Crash

I have integrated the Flutter Health package in my Flutter App and it works fine on android, although the page throws an error on iOS(P.S. The HealthKit Capability has been added). The UI Does not load and throws the following error

The code that the error points to is as follows,

dynamic stepCount() {
      double steps = 0.0;
      if (_countDataList.isNotEmpty)
        _countDataList.forEach((count) => steps += count.toJson()['value']);
      return steps;
  }

  double caloryCount() {
    double calories = 0;
    if (_caloriesDataList.isNotEmpty)
      _caloriesDataList.forEach((cal) => calories += cal.toJson()['value']);
    return calories;
  }