code: def test_special_cases(self):
      def check_special_case(strategy, graph_func, interchange, colors):
          graph = graph_func()
          coloring = nx.coloring.greedy_color(
              graph, strategy=strategy, interchange=interchange
          )
          if not hasattr(colors, "__len__"):
              colors = [colors]
          assert any(
              verify_length(coloring, n_colors) for n_colors in colors
          )
          assert verify_coloring(graph, coloring)
  
      for strategy, arglist in SPECIAL_TEST_CASES.items():
          for args in arglist:
              check_special_case(strategy, args[0], args[1], args[2])
  
imports: import itertools
  import pytest
  import networkx
label_desc: Use image node_id 2 for calling the TestColoring obj's underlying member method code with example usage: obj.test_special_cases() without return types