DateTime toLocal()

Returns this DateTime value in the local time zone.

Returns this if it is already in the local time zone. Otherwise this method is equivalent to:

new DateTime.fromMillisecondsSinceEpoch(millisecondsSinceEpoch,
                                        isUtc: false)

Source 

DateTime toLocal() {
  if (isUtc) {
    return new DateTime.fromMillisecondsSinceEpoch(millisecondsSinceEpoch,
                                                   isUtc: false);
  }
  return this;
}