def open(self):
        """
        Initiate an SSH connection to the host/port this object is bound to.

        This may include activating the configured gateway connection, if one
        is set.

        Also saves a handle to the now-set Transport object for easier access.

        Various connect-time settings (and/or their corresponding :ref:`SSH
        config options <ssh-config>`) are utilized here in the call to
        `SSHClient.connect <paramiko.client.SSHClient.connect>`. (For details,
        see :doc:`the configuration docs </concepts/configuration>`.)

        .. versionadded:: 2.0
        """
        # Short-circuit
        if self.is_connected:
            return
        err = "Refusing to be ambiguous: connect() kwarg '{}' was given both via regular arg and via connect_kwargs!"  # noqa
        # These may not be given, period
        for key in """
            hostname
            port
            username
        """.split():
            if key in self.connect_kwargs:
                raise ValueError(err.format(key))
        # These may be given one way or the other, but not both
        if (
            "timeout" in self.connect_kwargs
            and self.connect_timeout is not None
        ):
            raise ValueError(err.format("timeout"))
        # No conflicts -> merge 'em together
        kwargs = dict(
            self.connect_kwargs,
            username=self.user,
            hostname=self.host,
            port=self.port,
        )
        if self.gateway:
            kwargs["sock"] = self.open_gateway()
        if self.connect_timeout:
            kwargs["timeout"] = self.connect_timeout
        # Strip out empty defaults for less noisy debugging
        if "key_filename" in kwargs and not kwargs["key_filename"]:
            del kwargs["key_filename"]
        # Actually connect!
        self.client.connect(**kwargs)
        self.transport = self.client.get_transport()