block14.kt

class GetUserByIdUseCase(
	private val dispatcher: CoroutineDispatcher = Dispatcher.IO,
	private val userRepository: UserRepository
) {
	suspend fun invoke(id: String): User {
		return withContext(dispatcher) {
      userRepository.getUserById(id)      
    }
	}
}

class MyViewModel(
	private val getUserByIdUseCase: GetUserByIdUseCase
): Viewmodel {
	
		private val _user: MutableLiveData<User>
		val _user: LiveData<User>

		fun setUser(id: String) {
			viewModelScope.launch {
				_user.value = getUserByIdUseCase(id)
			}
		}

}