"      attr {"
      "        key: 'dtype'"
      "        value {"
      "          type: DT_FLOAT"
      "        }"
      "      }"
      "    }"
      "    node_def {"
      "      name: 'add1'"
      "      op: 'Add'"
      "      input: 'read0:value:0'"
      "      input: 'read1:value:0'"
      "      attr {"
      "        key: 'T'"
      "        value {"
      "          type: DT_FLOAT"

  }

  void SetViaProto(TF_OperationDescription* desc,
                   const std::vector<string>& list) {
    tensorflow::AttrValue attr;
    for (const string& v : list) {
      attr.mutable_list()->add_s(v);
    }
    string bytes;
    attr.SerializeToString(&bytes);
    TF_SetAttrValueProto(desc, tensorflow::kColocationAttrName, bytes.data(),
                         bytes.size(), s_);