使用RequestsCookieJar传多个cookie为什么只能抓到一个cookie

[fldx]

写了一个简单的示例程序，用requests模拟发请求，里面用到了RequestsCookieJar传cookie值，但从fiddler里抓到的数据包里只有一个cookie，试了很多次都是这样子，请问该如何正确使用RequestsCookieJar传多个cookie值呢？
代码如下

session = requests.Session()
	jar = requests.cookies.RequestsCookieJar()
	jar.set('PHPSESSID', 'bch0jetaeeo3andk0b3ckkvjs6', domain='btbtdy.net', path='/')
	jar.set('Hm_lvt_99249fb41a838398a3cc1c3ad2258fe7', '1542262837,1542667188,1542863132,1542891588', domain='btbtdy.net', path='/serviceweb')
	
	session.cookies.update(jar)
	rt = session.get(str_url, headers = head_content)

fiddler抓的结果如下

GET http://www.btbtdy.net/ HTTP/1.1
Host: www.btbtdy.net
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET4.0C; .NET4.0E; .NET CLR 2.0.50727)
Accept: image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash, application/xaml+xml, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*
Connection: keep-alive
Accept-Language: zh-cn
Referer: http://www.163.com
Cookie: PHPSESSID=bch0jetaeeo3andk0b3ckkvjs6

cookie明明加入了两个，但现在只抓到了一个，这是为何，请解。