Callback for the shot open button

        :returns: None
        :rtype: None
        :raises: None

def shot_open_callback(self, *args, **kwargs):
        """Callback for the shot open button

        :returns: None
        :rtype: None
        :raises: None
        """
        tf = self.browser.get_current_selection(1)
        if not tf:
            return
        if not os.path.exists(tf.path):
            msg = 'The selected shot does not exist: %s' % tf.path
            log.error(msg)
            self.statusbar.showMessage(msg)
            return
        js = JukeboxSignals.get()
        js.before_open_shot.emit(tf)
        self.open_shot(tf)
        js.after_open_shot.emit(tf)