class Global:
    host = 'http://xxx.org/'
    proxy=True
    proxyHost='http://127.0.0.1:8087/'
    opts=AttrDict(
        method='GET',
        headers={'Host':'xxxx.org',
              'User-Agent':'Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20100101 Firefox/12.0',
              'Accept':'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
              'Accept-Language':'en-us;q=0.5,en;q=0.3',
              'Accept-Encoding':'gzip, deflate',
              'Connection':'keep-alive',
              'Cookie':'xxxxxxx',
              'Cache-Control':'max-age=0'
              },
        assert_same_host=False
    )
    def getPool(self,proxy=None):
        if proxy is  None:
            proxy = self.proxy
        if(self.proxy):
            http_pool = urllib3.proxy_from_url(self.proxyHost)
        else:
            http_pool = urllib3.connection_from_url(self.host)
        return http_pool


class Conn:
    def __init__(self, proxy):
        self.proxy= proxy
        self.pool = Global().getPool(self.proxy)
    def swith(self):
        self.pool = Global().getPool(not self.proxy)
    def get(url, opts=Global.opts):
        try:
          self.pool.urlopen(
              method=opts.method,
              url= url,
              headers= opts.headers,
              assert_same_host=opts.assert_same_host
              )
        except TimeoutError, e:
            print()
        except MaxRetryError, e:
            # ..

class Conn:
    def get(url, opts=Global.opts):
        try:
          self.pool.urlopen(...)

def getPool(self,proxy=None):
    if proxy is  None:
        proxy = self.proxy
    if(self.proxy):
        http_pool = urllib3.proxy_from_url(self.proxyHost)
    else:
        http_pool = urllib3.connection_from_url(self.host)
    return http_pool