code: def test_fill_mask(self):
      inputs = self.tokenizer(
          ["Is 0 the <mask> Fibonacci <mask> ?"], return_tensors="pt"
      ).to(torch_device)
      outputs = self.model.generate(
          inputs["input_ids"],
          decoder_start_token_id=self.tokenizer.lang_code_to_id[
              "en_XX"
          ],
          num_beams=1,
      )
      prediction: str = self.tokenizer.batch_decode(
          outputs,
          clean_up_tokenization_spaces=True,
          skip_special_tokens=True,
      )[0]
      self.assertEqual(
          prediction,
          "0 0 the 0 the 0 the 0 the 0 the 0 the 0 the 0 the",
      )
  
imports: import copy
  import tempfile
  import unittest
  from transformers import PLBartConfig, is_torch_available
  from transformers.testing_utils import require_sentencepiece, require_tokenizers, require_torch, slow, torch_device
  from transformers.utils import cached_property
  from ...generation.test_generation_utils import GenerationTesterMixin
  from ...test_configuration_common import ConfigTester
  from ...test_modeling_common import ModelTesterMixin, ids_tensor
label_desc: Use image node_id 2 for calling the PLBartBaseIntegrationTest obj's underlying member method code with example usage: obj.test_fill_mask() without return types