package Ġcom . david h aj as . mov i eb rowser . use case . user session Ċ Ċ interface ĠUser Session Interactor Ġ{ ĊĠĠĠ Ġfun Ġis LoggedIn (): ĠBoolean ĊĠĠĠ Ġfun Ġis User Exists ( userName : ĠString ): ĠBoolean ĊĠĠĠ Ġ@ Throws ( Login Exception :: class , ĠException :: class ) ĊĠĠĠ Ġfun Ġlogin ( userName : ĠString , Ġpassword : ĠString ) ĊĠĠĠ Ġ@ Throws ( Register Exception :: class , ĠException :: class ) ĊĠĠĠ Ġfun Ġregister ( userName : ĠString , Ġpassword : ĠString , Ġpassword Again : ĠString ) Ċ }