Error: The method 'RaisedButton' isn't defined for the class 'ESewaPaymentButton'.

[nbnD]

In Flutter 3.3.2, I am getting such error:

/C:/flutter/.pub-cache/hosted/pub.dartlang.org/esewa_pnp-2.0.1/lib/esewa_pnp.dart:215:14: Error: The method 'RaisedButton' isn't defined for the class 'ESewaPaymentButton'.

• 'ESewaPaymentButton' is from 'package:esewa_pnp/esewa_pnp.dart' ('/C:/flutter/.pub-cache/hosted/pub.dartlang.org/esewa_pnp-2.0.1/lib/esewa_pnp.dart').
  Try correcting the name to the name of an existing method, or defining a method named 'RaisedButton'.
  child: RaisedButton(
  ^^^^^^^^^^^^

FAILURE: Build failed with an exception.

• Where:
  Script 'C:\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 1159

• What went wrong:
  Execution failed for task ':app:compileFlutterBuildDebug'.

Process 'command 'C:\flutter\bin\flutter.bat'' finished with non-zero exit value 1

• Try:

Run with --stacktrace option to get the stack trace.
Run with --info or --debug option to get more log output.
Run with --scan to get full insights.

• Get more help at https://help.gradle.org

BUILD FAILED in 3m 19s