def _parseServer(self, reactor, port, backlog=50, interface='::'):
        """
        Internal parser function for L{_parseServer} to convert the string
        arguments into structured arguments for the L{TCP6ServerEndpoint}

        @param reactor: An L{IReactorTCP} provider.

        @param port: The port number used for listening
        @type port: int

        @param backlog: Size of the listen queue
        @type backlog: int

        @param interface: The hostname to bind to
        @type interface: str
        """
        port = int(port)
        backlog = int(backlog)
        return TCP6ServerEndpoint(reactor, port, backlog, interface)

        Internal parser function for L{_parseServer} to convert the string
        arguments into structured arguments for the L{TCP6ServerEndpoint}

        @param reactor: An L{IReactorTCP} provider.

        @param port: The port number used for listening
        @type port: int

        @param backlog: Size of the listen queue
        @type backlog: int

        @param interface: The hostname to bind to
        @type interface: str
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/endpoints.py