How to use the libtmux.formats function in libtmux

def _list_sessions(self):
        """
        Return list of sessions in :py:obj:`dict` form.

        Retrieved from ``$ tmux(1) list-sessions`` stdout.

        The :py:obj:`list` is derived from ``stdout`` in
        :class:`common.tmux_cmd` which wraps :py:class:`subprocess.Popen`.

        Returns
        -------
        list of dict
        """

        sformats = formats.SESSION_FORMATS
        tmux_formats = ['#{%s}' % f for f in sformats]

        tmux_args = ('-F%s' % '\t'.join(tmux_formats),)  # output

        proc = self.cmd('list-sessions', *tmux_args)

        if proc.stderr:
            raise exc.LibTmuxException(proc.stderr)

        sformats = formats.SESSION_FORMATS
        tmux_formats = ['#{%s}' % format for format in sformats]
        sessions = proc.stdout

        # combine format keys with values returned from ``tmux list-sessions``
        sessions = [dict(zip(sformats, session.split('\t'))) for session in sessions]

Returns
        -------
        list of dict
        """

        sformats = formats.SESSION_FORMATS
        tmux_formats = ['#{%s}' % f for f in sformats]

        tmux_args = ('-F%s' % '\t'.join(tmux_formats),)  # output

        proc = self.cmd('list-sessions', *tmux_args)

        if proc.stderr:
            raise exc.LibTmuxException(proc.stderr)

        sformats = formats.SESSION_FORMATS
        tmux_formats = ['#{%s}' % format for format in sformats]
        sessions = proc.stdout

        # combine format keys with values returned from ``tmux list-sessions``
        sessions = [dict(zip(sformats, session.split('\t'))) for session in sessions]

        # clear up empty dict
        sessions = [
            dict((k, v) for k, v in session.items() if v) for session in sessions
        ]

        return sessions

wformats = ['session_name', 'session_id'] + formats.WINDOW_FORMATS
        tmux_formats = ['#{%s}' % format for format in wformats]

        proc = self.cmd(
            'list-windows',  # ``tmux list-windows``
            '-a',
            '-F%s' % '\t'.join(tmux_formats),  # output
        )

        if proc.stderr:
            raise exc.LibTmuxException(proc.stderr)

        windows = proc.stdout

        wformats = ['session_name', 'session_id'] + formats.WINDOW_FORMATS

        # combine format keys with values returned from ``tmux list-windows``
        windows = [dict(zip(wformats, window.split('\t'))) for window in windows]

        # clear up empty dict
        windows = [dict((k, v) for k, v in window.items() if v) for window in windows]

        # tmux < 1.8 doesn't have window_id, use window_name
        for w in windows:
            if 'window_id' not in w:
                w['window_id'] = w['window_name']

        if self._windows:
            self._windows[:] = []

        self._windows.extend(windows)

:term:`tmux(1)` will move window to the new pane if the
        ``split-window`` target is off screen. tmux handles the ``-d`` the
        same way as ``new-window`` and ``attach`` in
        :class:`Session.new_window`.

        By default, this will make the window the pane is created in
        active. To remain on the same window and split the pane in another
        target window, pass in ``attach=False``.
        """
        pformats = [
            'session_name',
            'session_id',
            'window_index',
            'window_id',
        ] + formats.PANE_FORMATS
        tmux_formats = ['#{%s}\t' % f for f in pformats]

        # '-t%s' % self.attached_pane.get('pane_id'),
        # 2013-10-18 LOOK AT THIS, rm'd it..
        tmux_args = tuple()

        if target:
            tmux_args += ('-t%s' % target,)
        else:
            tmux_args += ('-t%s' % self.panes[0].get('pane_id'),)

        if vertical:
            tmux_args += ('-v',)
        else:
            tmux_args += ('-h',)

The :py:obj:`list` is derived from ``stdout`` in
        :class:`util.tmux_cmd` which wraps :py:class:`subprocess.Popen`.

        Returns
        -------
        list
        """

        pformats = [
            'session_name',
            'session_id',
            'window_index',
            'window_id',
            'window_name',
        ] + formats.PANE_FORMATS
        tmux_formats = ['#{%s}\t' % f for f in pformats]

        proc = self.cmd('list-panes', '-a', '-F%s' % ''.join(tmux_formats))  # output

        if proc.stderr:
            raise exc.LibTmuxException(proc.stderr)

        panes = proc.stdout

        pformats = [
            'session_name',
            'session_id',
            'window_index',
            'window_id',
            'window_name',
        ] + formats.PANE_FORMATS

:param attach: make new window the current window after creating it,
                       default True.
        :type attach: bool
        :param start_directory: specifies the working directory in which the
            new created.
        :type start_directory: string
        :param target: ``target_pane`` to split.
        :type target: bool

        :rtype: :class:`Pane`

        """

        pformats = ['session_name', 'session_id',
                    'window_index', 'window_id'] + formats.PANE_FORMATS
        tmux_formats = ['#{%s}\t' % f for f in pformats]

        # '-t%s' % self.attached_pane().get('pane_id'),
        # 2013-10-18 LOOK AT THIS, rm'd it..
        tmux_args = tuple()

        if target:
            tmux_args += ('-t%s' % target,)
        else:
            tmux_args += ('-t%s' % self.panes[0].get('pane_id'),)

        tmux_args += (
            '-P', '-F%s' % ''.join(tmux_formats)  # output
        )

        if start_directory:

create the new window at the given index position. Default is empty
            string which will create the window in the next available position.
        window_shell : str
            execute a command on starting the window.  The window will close
            when the command exits.

            .. note::
                When this command exits the window will close.  This feature is
                useful for long-running processes where the closing of the
                window upon completion is desired.

        Returns
        -------
        :class:`Window`
        """
        wformats = ['session_name', 'session_id'] + formats.WINDOW_FORMATS
        tmux_formats = ['#{%s}' % f for f in wformats]

        window_args = tuple()

        if not attach:
            window_args += ('-d',)

        window_args += ('-P',)

        if start_directory:
            # as of 2014-02-08 tmux 1.9-dev doesn't expand ~ in new-window -c.
            start_directory = os.path.expanduser(start_directory)
            window_args += ('-c%s' % start_directory,)

        window_args += ('-F"%s"' % '\t'.join(tmux_formats),)  # output
        if window_name: