get_value method Null safety

Implementation

dynamic get_value() {
  if (this.is_none()) {
    return null;
  }
  if (this.is_bool()) {
    return this._getBool();
  }
  if (this.is_string()) {
    return this._getStr();
  }
  if (this.is_long()) {
    return this._getLong();
  }
  if (this.is_double()) {
    return this._getDouble();
  }
  if (this.is_data_ptr()) {
    return this._getDataPtr();
  }
}