new_contents: import sys
  import os.path
  from srtmod import srtmod
  
  def main(): 
      if len(sys.argv) < 5:
          print 'Usage: ' + sys.argv[0] +' <filename> <time amount> <time part>' \
              +' <operation> '
          print 'time part: (S)econds or (M)inutes'
          print 'operation: (/A)dd or (/D)iscount'
      else:
          try:
              file_name = sys.argv[1]
              time_amount = int(sys.argv[2])
              time_part = sys.argv[3]
              if time_part not in ('S', 'M'):
                  raise ValueError('Time part should be S or M')
              operation = sys.argv[4]
              if operation not in ('/A', '/D'):
                  raise ValueError('Operation should be /A or /D')
              srt = srtmod.SrtMod(file_name, time_amount, time_part, operation)
              if srt.process():
                  print 'Subtitle file was created successfully'
                  print 'file saved at :' + os.path.splitext(file_name)[0] + '(modified).srt'
          except OverflowError:
              print 'Exception: Invalid time amount for this operation'
          except ValueError as ex:
              print 'Exception: ' + str(ex)
  
  if __name__ == '__main__':
      main()
subject: add main file