code: def test_duplicated_head_ids(self):
      model = self.DummyTestModel()
      head1 = self.DummyTestHead()
      head2 = self.DummyTestHead()
      heads = {"dummy_block": [head1], "dummy_block2": [head2]}
      with self.assertRaises(ValueError):
          model.set_heads(heads)
  
      head2.unique_id = "head_id2"
      model.set_heads(heads)
  
file_path: ClassyVision/test/models_classy_block_test.py
imports: import unittest
  import torch
  import torch.nn
  from classy_vision.heads import ClassyHead
  from classy_vision.models import ClassyModel, ClassyModelHeadExecutorWrapper, ClassyModelWrapper
label_desc: Use image node_id 4 for calling the TestClassyBlock obj's underlying member method code with example usage: obj.test_duplicated_head_ids() without return types