如何使用dictConfig语法指定带有必需参数的日志处理程序类？

import logging
import logging.config

log_config = {
    'version': 1,
    'handlers': {
        'file_handler': {
            'class': 'logging.FileHandler',
            'filename': 'app.log',
            'level': 'DEBUG',
            'formatter': 'simple'
        }
    },
    'formatters': {
        'simple': {
            'format': '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
        }
    },
    'root': {
        'level': 'DEBUG',
        'handlers': ['file_handler']
    }
}

logging.config.dictConfig(log_config)

logger = logging.getLogger(__name__)
logger.debug('This is a debug message')
logger.info('This is an info message')
logger.warning('This is a warning message')
logger.error('This is an error message')
logger.critical('This is a critical message')