code: def test_spectral_ordering_tracemin_chol():
      """Test that "tracemin_chol" raises an exception."""
      pytest.importorskip("scipy")
      G = nx.barbell_graph(5, 4)
      with pytest.raises(nx.NetworkXError):
          nx.spectral_ordering(G, method="tracemin_chol")
  
imports: from math import sqrt
  import pytest
  import networkx
label_desc: Use image node_id 3 for calling a global function with example usage: test_spectral_ordering_tracemin_chol() without return types