How to use the aliyun-python-sdk-core-v3.aliyunsdkcore.http.protocol_type function in aliyun-python-sdk-core-v3

method="GET",
            headers={},
            protocol=PT.HTTP,
            content=None,
            port=None,
            key_file=None,
            cert_file=None,
            timeout=None):
        HttpRequest.__init__(
            self,
            host=host,
            url=url,
            method=method,
            headers=headers)
        self.__ssl_enable = False
        if protocol is PT.HTTPS:
            self.__ssl_enable = True
        self.__key_file = key_file
        self.__cert_file = cert_file
        self.__port = port
        self.__connection = None
        self._timeout = timeout
        self.set_body(content)