parentClass property
      
      ModelClassDefinition?
      get
      parentClass
      
    
    
Returns the ModelClassDefinition of the parent class.
If there is no parent class, null is returned.
Implementation
ModelClassDefinition? get parentClass {
  var extendsClass = this.extendsClass;
  if (extendsClass is! ResolvedInheritanceDefinition) return null;
  return extendsClass.classDefinition;
}