old_contents: """
  @brief      test log(time=1s)
  
  You should indicate a time in seconds. The program ``run_unittests.py``
  will sort all test files by increasing time and run them.
  """
  
  
  import sys
  import os
  import unittest
  import pandas
  
  
  try:
      import src
      import pyquickhelper
  except ImportError:
      path = os.path.normpath(
          os.path.abspath(
              os.path.join(
                  os.path.split(__file__)[0],
                  "..",
                  "..")))
      if path not in sys.path:
          sys.path.append(path)
      path = os.path.normpath(
          os.path.abspath(
              os.path.join(
                  os.path.split(__file__)[0],
                  "..",
                  "..",
                  "..",
                  "pyquickhelper",
                  "src")))
      if path not in sys.path:
          sys.path.append(path)
      import src
      import pyquickhelper
  
  from pyquickhelper import fLOG
  from src.ensae_teaching_cs import dfs2excel
  
  
  class TestSessionPandas (unittest.TestCase):
  
      def test_excel(self):
          fLOG(
              __file__,
              self._testMethodName,
              OutputPrint=__name__ == "__main__")
  
          df1 = pandas.DataFrame([{"name": "xavier", "school": "ENSAE"},
                                  {"name": "antoine", "school": "ENSAE"}])
  
          df2 = pandas.DataFrame([{"name": "xavier", "company": "Microsoft"},
                                  {"name": "antoine", "company": "Alephd"}])
  
          ef = os.path.abspath(
              os.path.join(
                  os.path.dirname(__file__),
                  "out_example.xlsx"))
          if os.path.exists(ef):
              os.remove(ef)
          dfs2excel({"ecole": df1, "boite": df2}, ef)
          assert os.path.exists(ef)
  
  if __name__ == "__main__":
      unittest.main()
  
new_contents: """
  @brief      test log(time=1s)
  
  You should indicate a time in seconds. The program ``run_unittests.py``
  will sort all test files by increasing time and run them.
  """
  
  
  import sys
  import os
  import unittest
  import pandas
  
  
  try:
      import src
      import pyquickhelper
  except ImportError:
      path = os.path.normpath(
          os.path.abspath(
              os.path.join(
                  os.path.split(__file__)[0],
                  "..",
                  "..")))
      if path not in sys.path:
          sys.path.append(path)
      path = os.path.normpath(
          os.path.abspath(
              os.path.join(
                  os.path.split(__file__)[0],
                  "..",
                  "..",
                  "..",
                  "pyquickhelper",
                  "src")))
      if path not in sys.path:
          sys.path.append(path)
      import src
      import pyquickhelper
  
  from pyquickhelper import fLOG
  from src.ensae_teaching_cs.pandas_helper import dfs2excel
  
  
  class TestSessionPandas (unittest.TestCase):
  
      def test_excel(self):
          fLOG(
              __file__,
              self._testMethodName,
              OutputPrint=__name__ == "__main__")
  
          df1 = pandas.DataFrame([{"name": "xavier", "school": "ENSAE"},
                                  {"name": "antoine", "school": "ENSAE"}])
  
          df2 = pandas.DataFrame([{"name": "xavier", "company": "Microsoft"},
                                  {"name": "antoine", "company": "Alephd"}])
  
          ef = os.path.abspath(
              os.path.join(
                  os.path.dirname(__file__),
                  "out_example.xlsx"))
          if os.path.exists(ef):
              os.remove(ef)
          dfs2excel({"ecole": df1, "boite": df2}, ef)
          assert os.path.exists(ef)
  
  if __name__ == "__main__":
      unittest.main()
  
subject: fix an import issue due to refactoring