Generating code from external schemas in JARs Error

I get the following error when I try to follow the documentation for adding an external library:

Could not find method dgsCodegen() [my.dependency:1.3.7'] on object of type org.gradle.api.internal.artifacts.dsl.dependencies.DefaultDependencyHandler.

With the following configuration:

    dependencies {
        dgsCodegen 'my.dependency:1.3.7'
    }

I believe the above configuration is in the wrong place in my build.gradle file, but am at a loss to find the correct place for it.

Thanks in advance.

Rick

Start by reviewing the documentation for adding an external library and the project's build.gradle dependency configuration. Reproduce the reported dgsCodegen() error, then clarify the correct placement or configuration so the documented setup works without that Gradle error.