inline constexpr char kSavedModelVariablesFilename[] = "variables";

// SavedModel SignatureDef keys for the initialization and train ops. Used in
// V2 SavedModels.
inline constexpr char kSavedModelInitOpSignatureKey[] = "__saved_model_init_op";
inline constexpr char kSavedModelTrainOpSignatureKey[] =
    "__saved_model_train_op";

// Key in the TensorBundle for the object graph proto.

      const SignatureDef& signature_def = key_and_signature_def.second;

      // It is safe to skip "__saved_model_init_op" since it is an internal
      // signature that is not user-accessible. This signature will be handled
      // in ConvertInitializer().
      if (sig_def_key == "__saved_model_init_op") {
        continue;
      }
      if (!import_all_signatures && exported_name_set.count(sig_def_key) == 0) {

    key: "saved_model_main_op"
    value {
      node_list {
        value: "NoOp"
      }
    }
  }
  signature_def {
    key: "__saved_model_init_op"
    value {
      outputs {
        key: "__saved_model_init_op"
        value {
          name: "NoOp"
          tensor_shape {
            unknown_rank: true
          }
        }
      }
    }
  }