al correr el emulador me sale este error: <code>Launching lib\main.dart on sdk gphone x86 arm in debug mode... Running Gradle task 'assem...

al correr el emulador me sale este error:

Launching lib\main.dart on sdk gphone x86 arm in debug mode...
Running Gradle task 'assembleDebug'...
lib/main.dart:11:19: Error: The method 'appbar' isn't defined for the class 'MyApp'.
 - 'MyApp' is from 'package:comestim_app/main.dart' ('lib/main.dart').
Try correcting the name to the name of an existing method, or defining a method named 'appbar'.
    var appbar2 = appbar(
                  ^^^^^^


FAILURE: Build failed with an exception.

* Where:
Script 'C:\src\flutter\packages\flutter_tools\gradle\flutter.gradle' line: 904

* What went wrong:
Execution failed for task ':app:compileFlutterBuildDebug'.
> Process 'command 'C:\src\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 11s
Exception: Gradle task assembleDebug failed with exit code 1

Alguien por favor me puede ayudar?