code: def backend_check_membership_accuracy_no_fit(attack, dataset, approx):
      (x_train, y_train), (x_test, y_test) = dataset
      # infer attacked feature
      inferred_train = attack.infer(x_train, y_train)
      inferred_test = attack.infer(x_test, y_test)
      # check accuracy
      backend_check_accuracy(inferred_train, inferred_test, approx)
  
file_path: adversarial-robustness-toolbox/tests/attacks/inference/membership_inference/test_label_only_gap_attack.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import logging
  import pytest
  from art.attacks.inference.membership_inference.label_only_gap_attack import LabelOnlyGapAttack
  from art.estimators.estimator import BaseEstimator
  from art.estimators.classification.classifier import ClassifierMixin
  from tests.attacks.utils import backend_test_classifier_type_check_fail
  from tests.utils import ARTTestException
label_desc: Use image node_id 4 for calling a global function with example usage: backend_check_membership_accuracy_no_fit(attack, dataset, approx) without return types