ClassyTaxiJava/app/src/main/java/com/sample/android/classytaxijava/billing/BillingClientLifecycle.java
TrivialDriveJava/app/src/main/java/com/sample/android/trivialdrivesample/billing/BillingDataSource.java

ClassyTaxiJava/app/src/main/java/com/sample/android/classytaxijava/ui/SingleLiveEvent.java
TrivialDriveJava/app/src/main/java/com/sample/android/trivialdrivesample/ui/SingleMediatorLiveEvent.java