def parameter(name, **kwargs):
    """
    Function decorator used to provide additional information for your
    function's parameter when it is converted to command.

    Parameters
    ----------
    name : str
        Name of the parameter.
    kwargs :
        Keyword arguments to pass to ArgumentParser's add_argument() method.
    """
    def decorator(func):
        if hasattr(func, 'parameter'):
            func.parameter[name] = kwargs
        else:
            func.parameter = {name: kwargs}
        return func
    return decorator