def print_helpers(parser, key):
    """
    Function that prints the helpers of a certain command
    
    :param parser: The parser which has all the helpers defined in a dict 
    :param key: The command which helper is called
    :return: The message of the helper or a message that it has no helpers
    """
    if len(parser.helpers[key]) != 0:
        msg = 'Las opciones para el comando ' + key + ' son: -'
        for opcion in parser.helpers[key]:
            msg += opcion + ' '
    else:
        msg = 'El comando no tiene opciones'
    return msg
