unable to use all functions of pspdfkit_flutter package

Question

i have installed pspdfkit package but it shows me error on its imports and i am unable to use its method

i searched every where on google but i didnt got anything i am unable to understand whats the issue and why some are installed and others not for example ican use

`import 'package:pspdfkit_flutter/pspdfkit.dart';
import 'package:pspdfkit_flutter/widgets/pspdfkit_widget.dart';
import 'package:pspdfkit_flutter/widgets/pspdfkit_widget_controller.dart';
`

but can use these

import 'package:pspdfkit_flutter/android_permission_status.dart';
import 'package:pspdfkit_flutter/configuration_options.dart';

especially extractAsset method