code: def test_gpt2_model_att_mask_past(self):
      config_and_inputs = self.model_tester.prepare_config_and_inputs()
      self.model_tester.create_and_check_gpt2_model_attention_mask_past(
          *config_and_inputs
      )
  
imports: import unittest
  from transformers import GPT2Config, is_tf_available
  from transformers.testing_utils import require_tf, require_tf2onnx, slow
  from ...test_configuration_common import ConfigTester
  from ...test_modeling_tf_common import TFModelTesterMixin, floats_tensor, ids_tensor, random_attention_mask
  from ...utils.test_modeling_tf_core import TFCoreModelTesterMixin
label_desc: Use image node_id 5 for calling the TFGPT2ModelTest obj's underlying member method code with example usage: obj.test_gpt2_model_att_mask_past() without return types