Nested Dagger Module

NetworkModule.kt

@Module(includes = [NetworkModule.OkHttpClientModule::class])
abstract class NetworkModule {

    @Binds abstract fun provideService(retrofitService: RetrofitService): Service

    @Module
    object OkHttpClientModule {

        @JvmStatic
        @Provides
        fun provideOkHttpClient(): OkHttpClient {
            return OkHttpClient.Builder().build()
        }
    }
}