      TF_EXCLUSIVE_LOCKS_REQUIRED(mu_) {
    if (tuple[index].has_value()) {
      return errors::InvalidArgument(
          "The tensor for index '", index, "' for key '", key.scalar<int64>()(),
          "' was already initialized '", dtypes_.size(), "'.");
    }

    return Status::OK();
  }
The program accesses or uses a pointer that has not been initialized.