private void AssertOnlyCityHasEventListener(string eventName, bool expected)
{
Assert(!_country.HasEventListener <MouseEvent>(eventName), "Country should not have event listener for " + eventName);
Assert(!_state.HasEventListener <MouseEvent>(eventName), "Stage should not have event listener for " + eventName);
Assert(expected == _city.HasEventListener <MouseEvent>(eventName), "City should " + (expected ? "" : "not") + " have event listener for " + eventName);
Assert(!_house.HasEventListener <MouseEvent>(eventName), "House should have event listener for " + eventName);
}