code: def test_back_to_default(self):
      model = self.get_model()
      model.eval()
      input_data = self.get_input_samples((1, 128), config=model.config)
      output1 = model(**input_data)
      tokenizer = AutoTokenizer.from_pretrained("tests/fixtures/SiBERT")
      model.add_embeddings("test", tokenizer)
      self.assertEqual(model.active_embeddings, "test")
      model.set_active_embeddings("default")
      output2 = model(**input_data)
      self.assertEqual(model.active_embeddings, "default")
      self.assertTrue(torch.equal(output1[0], output2[0]))
  
file_path: adapters/tests/test_adapter_embeddings.py
imports: import copy
  import tempfile
  import torch
  from adapters import AutoAdapterModel
  from transformers import AutoTokenizer, Trainer, TrainingArguments
  from transformers.testing_utils import require_torch, torch_device
label_desc: Use image node_id 6 for calling the EmbeddingTestMixin obj's underlying member method code with example usage: obj.test_back_to_default() without return types