tmux determine if a pane is marked
<p>I want to create a tmux keybind which sends a set of keystrokes to the marked pane. This is convenient for implementing a hotkey that runs something so I don't have to manually focus another pane and then come back.</p>

<p>But I'd like for this key to not do anything if there's no marked pane present. I've looked in the manpage and found nothing obvious that I can use to check this state.</p>