old_contents: ###############################################################################
  #
  # Tests for XlsxWriter.
  #
  # Copyright (c), 2013-2016, John McNamara, jmcnamara@cpan.org
  #
  
  import unittest
  
  from xlsxwriter.chartsheet import Chartsheet
  from xlsxwriter.worksheet import Worksheet
  from ...workbook import Workbook
  
  
  class MyWorksheet(Worksheet):
      pass
  
  
  class MyChartsheet(Chartsheet):
      pass
  
  
  class MyWorkbook(Workbook):
      chartsheet_class = MyChartsheet
      worksheet_class = MyWorksheet
  
  
  class TestCustomSheet(unittest.TestCase):
      """
      Test the Workbook _check_sheetname() method.
  
      """
  
      def setUp(self):
          self.workbook = Workbook()
  
      def test_check_chartsheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_chartsheet()
          assert isinstance(sheet, Chartsheet)
  
          sheet = self.workbook.add_chartsheet(chartsheet_class=MyChartsheet)
          assert isinstance(sheet, MyChartsheet)
  
      def test_check_worksheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_worksheet()
          assert isinstance(sheet, Worksheet)
  
          sheet = self.workbook.add_worksheet(worksheet_class=MyWorksheet)
          assert isinstance(sheet, MyWorksheet)
  
  
  class TestCustomWorkBook(unittest.TestCase):
      """
      Test the Workbook _check_sheetname() method.
  
      """
  
      def setUp(self):
          self.workbook = MyWorkbook()
  
      def test_check_chartsheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_chartsheet()
          assert isinstance(sheet, MyChartsheet)
  
      def test_check_worksheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_worksheet()
          assert isinstance(sheet, MyWorksheet)
  
new_contents: ###############################################################################
  #
  # Tests for XlsxWriter.
  #
  # Copyright (c), 2013-2016, John McNamara, jmcnamara@cpan.org
  #
  
  import unittest
  
  from xlsxwriter.chartsheet import Chartsheet
  from xlsxwriter.worksheet import Worksheet
  from ...workbook import Workbook
  
  
  class MyWorksheet(Worksheet):
      pass
  
  
  class MyChartsheet(Chartsheet):
      pass
  
  
  class MyWorkbook(Workbook):
      chartsheet_class = MyChartsheet
      worksheet_class = MyWorksheet
  
  
  class TestCustomSheet(unittest.TestCase):
      """
      Test the Workbook _check_sheetname() method.
  
      """
  
      def setUp(self):
          self.workbook = Workbook()
  
      def tearDown(self):
          self.workbook.fileclosed = 1
  
      def test_check_chartsheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_chartsheet()
          assert isinstance(sheet, Chartsheet)
  
          sheet = self.workbook.add_chartsheet(chartsheet_class=MyChartsheet)
          assert isinstance(sheet, MyChartsheet)
  
      def test_check_worksheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_worksheet()
          assert isinstance(sheet, Worksheet)
  
          sheet = self.workbook.add_worksheet(worksheet_class=MyWorksheet)
          assert isinstance(sheet, MyWorksheet)
  
  
  class TestCustomWorkBook(unittest.TestCase):
      """
      Test the Workbook _check_sheetname() method.
  
      """
  
      def setUp(self):
          self.workbook = MyWorkbook()
  
      def tearDown(self):
          self.workbook.fileclosed = 1
  
      def test_check_chartsheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_chartsheet()
          assert isinstance(sheet, MyChartsheet)
  
      def test_check_worksheet(self):
          """Test the _check_sheetname() method"""
          sheet = self.workbook.add_worksheet()
          assert isinstance(sheet, MyWorksheet)
  
subject: Fix test warning under Python 3.4.1.