old_contents: #! python3
  # renameDates.py - Renames filenames with American MM-DD-YYYY date format
  # to European DD-MM-YYYY.
  
  import shutil, os, re
  
  # Create a regex that matches files with the American date format.
  datePattern = re.compile(r"""
          ^(.*?)          # all text before the date
          ((0|1)?\d)-     # one or two digits for the month
          ((0|1|2|3)?\d)- # one or two digits for the day
          ((19|20)\d\d)   # four digits for the year
          (.*?)$          # all the text after the date
          """, re.VERBOSE)
  
  # Loop over the files in the working directory.
  for amerFilename in os.listdir('.'):
      mo = datePatter.search(amerFilename)
  
      # Skip files without a date.
      if mo == None:
          continue
  
      # Get the different parts of the filename.
      beforePart = mo.group(1)
      monthPart = mo.group(2)
      dayPart = mo.group(4)
      yearPart = mo.group(6)
      afterPart = mo.group(8)
  
      # Form the European-style filename.
      euroFilename = beforePart + dayPart + '-' + monthPart + '-' + yearPart + afterPart
  
      # Get the full, absolute file paths.
      absWorkingDir = os.path.abspath('.')
      amerFilename = os.path.join(absWorkingDir, amerFilename)
      euroFilename = os.path.join(absWorkingDir, euroFilename)
  
      # Rename the files.
      print('Renaming "%s" to "%s"...' % (amerFilename, euroFilename))  # DEBUG
      #shutil.move(amerFilename, euroFilename)  # uncomment after testing
  
new_contents: #! python3
  # renameDates.py - Renames filenames with American MM-DD-YYYY date format
  # to European DD-MM-YYYY.
  
  import shutil, os, re
  
  # Create a regex that matches files with the American date format.
  datePattern = re.compile(r"""
          ^(.*?)          # all text before the date
          ((0|1)?\d)-     # one or two digits for the month
          ((0|1|2|3)?\d)- # one or two digits for the day
          ((19|20)\d\d)   # four digits for the year
          (.*?)$          # all the text after the date
          """, re.VERBOSE)
  
  # Loop over the files in the working directory.
  for amerFilename in os.listdir('.'):
      mo = datePattern.search(amerFilename)
  
      # Skip files without a date.
      if mo == None:
          continue
  
      # Get the different parts of the filename.
      beforePart = mo.group(1)
      monthPart = mo.group(2)
      dayPart = mo.group(4)
      yearPart = mo.group(6)
      afterPart = mo.group(8)
  
      # Form the European-style filename.
      euroFilename = beforePart + dayPart + '-' + monthPart + '-' + yearPart + afterPart
  
      # Get the full, absolute file paths.
      absWorkingDir = os.path.abspath('.')
      amerFilename = os.path.join(absWorkingDir, amerFilename)
      euroFilename = os.path.join(absWorkingDir, euroFilename)
  
      # Rename the files.
      print('Renaming "%s" to "%s"...' % (amerFilename, euroFilename))  # DEBUG
      #shutil.move(amerFilename, euroFilename)  # uncomment after testing
  
subject: Update P04_renameDates: fixed typo