code: def test_set_default_language(self):
      config = self.model_tester.prepare_config_and_inputs()[0]
      model = XmodForMaskedLM(config=config)
      model.set_default_language("en_XX")
      self.assertEqual(model.config.default_language, "en_XX")
      with self.assertRaises(ValueError):
          model.set_default_language("xx_XX")
  
imports: import unittest
  from transformers import XLMRobertaTokenizer, is_torch_available
  from transformers.testing_utils import require_sentencepiece, require_tokenizers, require_torch, slow, torch_device
  from ...generation.test_utils import GenerationTesterMixin
  from ...test_configuration_common import ConfigTester
  from ...test_modeling_common import ModelTesterMixin, floats_tensor, ids_tensor, random_attention_mask
  from ...test_pipeline_mixin import PipelineTesterMixin
label_desc: Use image node_id 17 for calling the XmodModelTest obj's underlying member method code with example usage: obj.test_set_default_language() without return types