const ::google::protobuf::Map<std::string, ::tensorflow::TensorProto>& map) {
  std::set<std::string> keys;
  for (const auto& it : map) {
    keys.insert(it.first);
  }
  return keys;
}

Status GetInputValues(
    const SignatureDef& signature,
    const ::google::protobuf::Map<std::string, ::tensorflow::TensorProto>& request_inputs,
    std::vector<std::pair<string, Tensor>>& inputs) {
  const TensorProto* tensor_proto;