docstr: Ensure an explicit exception is raised for GPT2 w/ MLM 
docstr_tok: ["Ensure","an","explicit","exception","is","raised","for","GPT2","w\/","MLM"]
code: def test_exception_gpt2(self):
      """
      Ensure an explicit exception is raised for GPT2 w/ MLM
      """
      with self.assertRaises(FinetuneError):
          model = MaskedLanguageModel(base_model=GPT2)
  
file_path: finetune/tests/test_masked_language_model.py
imports: import os
  import glob
  import unittest
  import warnings
  from pathlib import Path
  import pandas
  import numpy
  from finetune import MaskedLanguageModel, Classifier
  from finetune.errors import FinetuneError
  from finetune.base_models import GPT2, BERT, RoBERTa
label_desc: Use image node_id 7 for calling the TestMaskedLanguageModel obj's underlying member method code with example usage: obj.test_exception_gpt2() without return types