code: private void makeClassImplementParcelable(PsiElementFactory elementFactory, JavaCodeStyleManager styleManager) {
      final PsiClassType[] implementsListTypes = psiClass.getImplementsListTypes();
      final String implementsType = "android.os.Parcelable";
  
      for (PsiClassType implementsListType : implementsListTypes) {
        PsiClass resolved = implementsListType.resolve();
  
        // Already implements Parcelable, no need to add it
        if (resolved != null && implementsType.equals(resolved.getQualifiedName())) {
          return;
        }
      }
  
      PsiJavaCodeReferenceElement implementsReference =
          elementFactory.createReferenceFromText(implementsType, psiClass);
      PsiReferenceList implementsList = psiClass.getImplementsList();
  
      if (implementsList != null) {
        styleManager.shortenClassReferences(implementsList.add(implementsReference));
      }
    }
docs: Make the class implementing Parcelable