addInput method
Implementation
addInput(int number){
key = number.toString();
if (number >= 0 && number <= 10) {
inputs.removeWhere((e) => e.isEmpty);
if(inputs.length != _length) inputs.add(number.toString());
value = inputs.join().trim();
last = inputs.last.toString();
isFull = inputs.length == _length;
isEmpty = false;
_fillList();
} else {
Exception("number must be >= 0 and <= 10");
}
notifyListeners();
}