new_contents: from tempfile import TemporaryFile
  from contextlib import contextmanager
  
  from penchy.compat import unittest, nested
  
  
  class NestedTest(unittest.TestCase):
      def test_reraising_exception(self):
          e = Exception('reraise this')
          with self.assertRaises(Exception) as raised:
              with nested(TemporaryFile(), TemporaryFile()) as (a, b):
                  raise e
  
          self.assertEqual(raised.exception, e)
  
      def test_raising_on_exit(self):
          @contextmanager
          def raising_cm(exception):
              yield
              raise exception
  
          on_exit = Exception('throw on exit')
          with self.assertRaises(Exception) as raised:
              with nested(raising_cm(on_exit)):
                  pass
          self.assertEqual(raised.exception, on_exit)
  
subject: Add tests for penchy.compat.nested.