code: def add_args(p):
      
      # dictionary for adding arguments
      dadd_args = {
          '--opfile': {
              'default': '',
              'metavar': 'f',
              'type': str,
              'help': 'Specify a parameter file '
                      '(default: "sim/${exkey}_params.txt")'}}
      p = utils.add_args(p, dadd_args)
      return p
docs: Update parser with tool specific arguments.
  
      This overwrites was is done in utils.uns_args.