new_contents: import argparse
  
  """
  A formatter class remove duplicated metavar
  
  From: http://stackoverflow.com/a/16969505/3962533
  """
  class SingleMetavarHelpFormatter(argparse.HelpFormatter):
      def _format_action_invocation(self, action):
          if not action.option_strings:
              metavar, = self._metavar_formatter(action, action.dest)(1)
              return metavar
  
          else:
              parts = []
  
              # if the Optional doesn't take a value, format is:
              #    -s, --long
              if action.nargs == 0:
                  parts.extend(action.option_strings)
  
              # if the Optional takes a value, format is:
              #    -s ARGS, --long ARGS
              else:
                  default = action.dest.upper()
                  args_string = self._format_args(action, default)
  
                  ## THIS IS THE PART REPLACED
                  #~ for option_string in action.option_strings:
                      #~ parts.append('%s %s' % (option_string, args_string)) ### this is change
                  ## /SECTION REPLACED
  
                  ## NEW CODE:
                  parts.extend(action.option_strings)
                  parts[-1] += ' %s' % args_string
                  ## /NEW CODE
              return ', '.join(parts)
  
subject: Add help_formatter.py