return a command line parser. It is used when generating the documentation

def _cmd_line_parser():
    '''
    return a command line parser. It is used when generating the documentation
    '''

    parser = argparse.ArgumentParser()
    parser.add_argument('--path',
                        help=('path to test files, '
                              'if not provided the script folder is used'))
    parser.add_argument('--text_output',
                        action='store_true',
                        help='option to save the results to text file')
    parser.add_argument('--format',
                        default='rst',
                        nargs='?',
                        choices=['rst', 'md'],
                        help='text formatting')

    return parser