  explicit SpaceToBatchOp(OpKernelConstruction* ctx) : XlaOpKernel(ctx) {
    OP_REQUIRES_OK(ctx, ctx->GetAttr("block_size", &block_size_));
    OP_REQUIRES(
        ctx, block_size_ > 1,
        errors::InvalidArgument("Block size should be > 1: ", block_size_));
  }
  explicit SpaceToBatchOp(OpKernelConstruction* ctx) : XlaOpKernel(ctx) {
    OP_REQUIRES_OK(ctx, ctx->GetAttr("block_size", &block_size_));
    OP_REQUIRES(
        ctx, block_size_ > 1,
        errors::InvalidArgument("Block size should be > 1: ", block_size_));
  }