报错：
webdriver.PhantomJS()
raise exception_class(value)
selenium.common.exceptions.WebDriverException: Message: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html><head>
<title>Proxy error: 502 Server dropped connection.</title>
</head><body>
<h1>502 Server dropped connection</h1>
<p>The following error occurred while trying to access <strong>http://127.0.0.1:5809/wd/hub/session</strong>:<br><br>
<strong>502 Server dropped connection</strong></p>
<hr>Generated Thu, 28 Dec 2017 03:20:49 GMT by Polipo on <em>PC201504121304:8123</em>.
</body></html>
连接不上的原因：
shadowsocks开着全局代理