class_docstr: Test that model classes can predict.
class_docstr_tok: ["Test","that","model","classes","can","predict","."]
code: def test_gpt2(self):
      # Run prediction to ensure no failure.
      model_path = "https://storage.googleapis.com/what-if-tool-resources/lit-models/gpt2.tar.gz"
      model = pretrained_lms.GPT2LanguageModel(model_path)
      model_in = [{"text": "test text"}, {"text": "longer test text"}]
      model_out = list(model.predict(model_in))
  
      # Sanity-check output vs output spec.
      self.assertLen(model_out, 2)
      for key in model.output_spec().keys():
          self.assertIn(key, model_out[0].keys())
  
imports: from absl.testing import absltest
  from lit_nlp.examples.models import pretrained_lms
label_desc: Use image node_id 2 for calling the PretrainedLmsIntTest obj's underlying member method code with example usage: obj.test_gpt2() without return types