setAttributeValue method
Parses value and sets this instances value.
Implementation
@override
void setAttributeValue(Object? value) {
  var valuesList = parseListOfStrings(value, delimiterPattern, true);
  if (valuesList.isEmpty) {
    _values = [];
  } else if (_values.length == 1 && valuesList.length == 1) {
    _values[0] = parseString(valuesList[0])!;
  } else {
    _values = valuesList;
  }
}