'Given path to configuration file, read it in as a ConfigParser
object and return that object.'

def _read_config_file(self, config_filename):

    if os.path.isfile(config_filename):
        self.__config_file = config_filename
        logger.debug('Reading    config    from    {0}'.format(config_filename))
        config_fp = io.open(config_filename, 'r', encoding='utf-8')
    else:
        raise JJBConfigException('A    valid    configuration    file    is    required.    \n{0}    is    not    valid.'.format(config_filename))
    return config_fp
