>();      // Create an output tensor     Tensor* output_tensor = NULL;     OP_REQUIRES(context, TensorShapeUtils::IsVector(input_tensor.shape()),                 errors::InvalidArgument("ZeroOut expects a 0-D vector."));     OP_REQUIRES_OK(context, context->allocate_output(0, input_tensor.shape(),                                                      &output_tensor));     // We're using saved attr to validate potentially dynamic input     // So we check that preserve_index is in range     OP_REQUIRES(context, preserve_index < input.dimension(0),                 errors::InvalidArgument("preserve_index out of range"));      auto output_flat = output_tensor->flat<