Set proxy for requests session

def set_proxy(self, proxy):
        """
        Set proxy for requests session
        """
        # TODO: Validate proxy url format

        if proxy is None:
            self.driver.proxies = {'http': None,
                                   'https': None
                                   }
        else:
            self.driver.proxies = {'http': proxy,
                                   'https': proxy
                                   }

        self.current_proxy = proxy