string(275) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%AE%80%E8%BF%B0%E4%BB%80%E4%B9%88%E6%98%AF%E5%9F%BA%E5%B0%BC%E7%B3%BB%E6%95%B0%E7%9A%84%E7%89%B9%E7%82%B9 => Failed to connect to 101.91.112.32 port 38195: Connection refused"
简述什么是基尼系数的特点
