def add_cell_argument(self, name, help, required=False):
    """ Add a cell only argument.

    Args:
      name: name of the argument. No need to start with "-" or "--".
      help: the help string of the argument.
      required: Whether it is required in cell content.
    """

    for action in self._actions:
      if action.dest == name:
        raise ValueError('Arg "%s" was added by add_argument already.' % name)

    self._cell_args[name] = {'required': required, 'help': help}
Add a cell only argument.

    Args:
      name: name of the argument. No need to start with "-" or "--".
      help: the help string of the argument.
      required: Whether it is required in cell content.