private static void moveSubClassExtendsToImplements(List<PsiClass> inheritors) {
      final PsiClass oldClass = inheritors.get(0);
      for (int i = 1; i < inheritors.size(); i++) {
        final PsiClass inheritor = inheritors.get(i);
        final PsiReferenceList extendsList = inheritor.getExtendsList();
        if (extendsList == null) {
          continue;
        }
        final PsiReferenceList implementsList = inheritor.getImplementsList();
        moveReference(extendsList, implementsList, oldClass);
      }
    }
private static void moveSubClassExtendsToImplements(List<PsiClass> inheritors)