message: Provide `InputDatasets()` implementation for LoadDataset.
diff: @@ -212,6 +212,11 @@ class LoadDatasetOp::Dataset : public DatasetBase {
  return captured_func_->CheckExternalState();
  }
  + Status InputDatasets(std::vector<const DatasetBase*>* inputs) const override {
  + inputs->clear();
  + return Status::OK();
  + }
  +
  protected:
  Status AsGraphDefInternal(SerializationContext* ctx,
  DatasetGraphDefBuilder* b,
  