createEmptyListProperty<T>  method 
    Null safety
- {String? propertyName}
 
Short hand helper function for initializing an empty EmpireListProperty.
See EmpireProperty for propertyName usages.
Example
late final EmpireListProperty planets;
planets = createEmptyListProperty();
Implementation
EmpireListProperty<T> createEmptyListProperty<T>({String? propertyName}) {
  return EmpireListProperty([], this, propertyName: propertyName);
}