#coding=utf-8
import requests,sys,socket
from requests_toolbelt.adapters import source
reload(sys)
sys.setdefaultencoding('utf-8')


s = requests.Session()
new_source = source.SourceAddressAdapter('192.168.4.2')
s.mount('http://', new_source)
s.mount('https://', new_source)
print s.get('http://xxx.xxx.xxx.xxx:8091/')

pip install requests_toolbelt