【python2】使用固定源端口发送http请求

背景需求：相同五元组信息的TCP会话
代码：

import requests
from requests.adapters import HTTPAdapter
from requests.adapters import DEFAULT_POOLBLOCK
from urllib3 import PoolManager

######################
#     python 2.x     #
######################

class SourcePortAdapter(HTTPAdapter):
    """Tran