code: def get_filenames(options):
  
      '''Get the filenames from the command line, optionally sorted by
  number, so that IMG_10.png is re-arranged to come after IMG_9.png.
  This is a nice feature because some scanner programs (like Image
  Capture on Mac OS X) automatically number files without leading zeros,
  and this way you can supply files using a wildcard and still have the
  pages ordered correctly.
  
      '''
  
      if not options.sort_numerically:
          return options.filenames
  
      filenames = []
  
      for filename in options.filenames:
          basename = os.path.basename(filename)
          root, _ = os.path.splitext(basename)
          matches = re.findall(r'[0-9]+', root)
          if matches:
              num = int(matches[-1])
          else:
              num = -1
          filenames.append((num, filename))
  
      return [fn for (_, fn) in sorted(filenames)f get_filenames(options):
  
      '''Get the filenames from the command line, optionally sorted by
  number, so that IMG_10.png is re-arranged to come after IMG_9.png.
  This is a nice feature because some scanner programs (like Image
  Capture on Mac OS X) automatically number files without leading zeros,
  and this way you can supply files using a wildcard and still have the
  pages ordered correctly.
  
      '''
  
      if not options.sort_numerically:
          return options.filenames
  
      filenames = []
  
      for filename in options.filenames:
          basename = os.path.basename(filename)
          root, _ = os.path.splitext(basename)
          matches = re.findall(r'[0-9]+', root)
          if matches:
              num = int(matches[-1])
          else:
              num = -1
          filenames.append((num, filename))
  
      return [fn for (_, fn) in sorted(filenames)]
docs: Get the filenames from the command line, optionally sorted by
  number, so that IMG_10.png is re-arranged to come after IMG_9.png.
  This is a nice feature because some scanner programs (like Image
  Capture on Mac OS X) automatically number files without leading zeros,
  and this way you can supply files using a wildcard and still have the
  pages ordered correctly.