code: def test_batch_split_adapter_head(self):
      model = AutoAdapterModel.from_config(self.config())
      self.add_head(model, "a")
      self.add_head(model, "b")
      model.add_adapter("a")
      model.add_adapter("b")
      model.add_adapter("c")
      model.set_active_adapters(
          BatchSplit(Stack("c", "a"), "b", batch_sizes=[2, 1])
      )
  
      in_data = self.get_input_samples(config=model.config)
      model.to(torch_device)
      out = model(**in_data)
  
      self.assertEqual(2, len(out))
      self.assertTrue(isinstance(model.active_head, BatchSplit))
  
imports: import os
  import tempfile
  import torch
  import adapters
  from adapters import ADAPTER_MODEL_MAPPING, AdapterSetup, AutoAdapterModel
  from adapters.composition import BatchSplit, Stack
  from transformers import AutoModelForSequenceClassification
  from transformers.testing_utils import require_torch, torch_device
  from .methods import create_twin_models
label_desc: Use image node_id 17 for calling the PredictionHeadModelTestMixin obj's underlying member method code with example usage: obj.test_batch_split_adapter_head() without return types