code: def test_missing_half_edge(self):
      embedding = nx.PlanarEmbedding()
      embedding.add_half_edge(1, 2)
      with pytest.raises(nx.NetworkXException):
          # Invalid structure because other half edge is missing
          embedding.check_structure()
  
imports: import pytest
  import networkx
  from networkx.algorithms.planarity import check_planarity_recursive, get_counterexample, get_counterexample_recursive
label_desc: Use image node_id 6 for calling the TestPlanarEmbeddingClass obj's underlying member method code with example usage: obj.test_missing_half_edge() without return types