lack of namespace of build.gradle

[yoer]

Launching lib/main.dart on HMA L29 in debug mode...
Running Gradle task 'assembleDebug'...

FAILURE: Build failed with an exception.

• What went wrong:
  A problem occurred configuring project ':flutter_dtmf'.

Could not create an instance of type com.android.build.api.variant.impl.LibraryVariantBuilderImpl.
Namespace not specified. Specify a namespace in the module's build file. See https://d.android.com/r/tools/upgrade-assistant/set-namespace for information about setting the namespace.

 If you've specified the package attribute in the source AndroidManifest.xml, you can use the AGP Upgrade Assistant to migrate to the namespace value in the build file. Refer to https://d.android.com/r/tools/upgrade-assistant/agp-upgrade-assistant for general information about using the AGP Upgrade Assistant.

• Try:

Run with --stacktrace option to get the stack trace.
Run with --info or --debug option to get more log output.
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Get more help at https://help.gradle.org.

BUILD FAILED in 1s
Error: Gradle task assembleDebug failed with exit code 1