<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _read_config_file(args):
 """Decrypt config file, returns a tuple with stages and config."""

    stage = args.stage
    with open(args.config, 'rt') as f:
        config = yaml.safe_load(f.read())
    STATE['stages'] = config['stages']
    config['config'] = _decrypt_item(config['config'], stage=stage, key='',
                                     render=True)
    return config['stages'], config['config']