restarting method Null safety

void restarting(
  1. void singleStepOnDone(
    1. CalculatorError?
    )?
)

Implementation

void restarting(void Function(CalculatorError?)? singleStepOnDone) {
  _singleStepOnDone = singleStepOnDone;
  model.program.suspendedProgram = null;
  model.displayDisabled = true;
  _stopNext = singleStepOnDone != null;
}