### Question:
StatefulFunctionsSavepointCreator { public StatefulFunctionsSavepointCreator withStateBootstrapFunctionProvider( FunctionType functionType, StateBootstrapFunctionProvider bootstrapFunctionProvider) { stateBootstrapFunctionRegistry.register(functionType, bootstrapFunctionProvider); return this; } StatefulFunctionsSavepointCreator(int maxParallelism); StatefulFunctionsSavepointCreator withFsStateBackend(); StatefulFunctionsSavepointCreator withBootstrapData(
      DataSet<IN> bootstrapDataset, BootstrapDataRouterProvider<IN> routerProvider); StatefulFunctionsSavepointCreator withStateBootstrapFunctionProvider(
      FunctionType functionType, StateBootstrapFunctionProvider bootstrapFunctionProvider); void write(String path);  }### Answer:
@Test(expected = IllegalArgumentException.class) public void duplicateStateBootstrapFunctionProvider() { final StatefulFunctionsSavepointCreator testCreator = new StatefulFunctionsSavepointCreator(1); testCreator.withStateBootstrapFunctionProvider( new FunctionType("ns", "test"), ignored -> new NoOpStateBootstrapFunction()); testCreator.withStateBootstrapFunctionProvider( new FunctionType("ns", "test"), ignored -> new NoOpStateBootstrapFunction()); }