code: def testPreference(self):
      g = Graph.Preference(100, [1, 1], [[1, 0], [0, 1]])
      self.assertTrue(isinstance(g, Graph))
      self.assertEqual(len(g.connected_components()), 2)
  
      g = Graph.Preference(
          100, [1, 1], [[1, 0], [0, 1]], attribute="type"
      )
      types = g.vs.get_attribute_values("type")
      self.assertTrue(min(types) == 0 and max(types) == 1)
  
file_path: python-igraph/tests/test_games.py
imports: import unittest
  from igraph import Graph, InternalError, Layout
label_desc: Use image node_id 4 for calling the GameTests obj's underlying member method code with example usage: obj.testPreference() without return types