Starts accepting connections on the given port.

        This method may be called more than once to listen on multiple ports.
        `listen` takes effect immediately; it is not necessary to call
        `TCPServer.start` afterwards.  It is, however, necessary to start
        the `.IOLoop`.

def listen(self, port: int, address: str = "") -> None:
        """Starts accepting connections on the given port.

        This method may be called more than once to listen on multiple ports.
        `listen` takes effect immediately; it is not necessary to call
        `TCPServer.start` afterwards.  It is, however, necessary to start
        the `.IOLoop`.
        """
        sockets = bind_sockets(port, address=address)
        self.add_sockets(sockets)