old_contents: import unittest
  from .context import Undirected, BFS, bipartite
  
  EDGES = [
      [8, 4],
      [4, 1],
      [1, 0],
      [1, 3],
      [1, 5],
      [0, 2],
      [2, 2],
      [2, 6],
      [2, 7]
  ]
  
  CASES = [
      [[], True],
      [[[3, 7]], False],
      [[[3, 5]], False],
      [[[7, 9], [9, 3]], True],
      [[[8, 1]], False]
  ]
  
  
  class TestBipartite(unittest.TestCase):
      def test_bipartite(self):
          graph = Undirected()
          for x, y in EDGES:
              graph.insert_edge(x, y)
  
          for case, expected in CASES:
              copy = graph.copy()
              for x, y in case:
                  copy.insert_edge(x, y)
              self.assertEqual(expected, bipartite(copy), str(case) + ' fails')
  
new_contents: import unittest
  from .context import Undirected, bipartite
  
  EDGES = [
      [8, 4],
      [4, 1],
      [1, 0],
      [1, 3],
      [1, 5],
      [0, 2],
      [2, 2],
      [2, 6],
      [2, 7]
  ]
  
  CASES = [
      [[], True],
      [[[3, 7]], False],
      [[[3, 5]], False],
      [[[7, 9], [9, 3]], True],
      [[[8, 1]], False]
  ]
  
  
  class TestBipartite(unittest.TestCase):
      def test_bipartite(self):
          graph = Undirected()
          for x, y in EDGES:
              graph.insert_edge(x, y)
  
          for case, expected in CASES:
              copy = graph.copy()
              for x, y in case:
                  copy.insert_edge(x, y)
              self.assertEqual(expected, bipartite(copy), str(case) + ' fails')
  
subject: Remove unnecessary import