Wait until all of given UI proxies show up before timeout.
        All UI proxies will be polled periodically. See option :py:class:`poll_interval <poco.pocofw.Poco>` in 
        ``Poco``'s initialization for more details.

        Args:
            objects (Iterable<:py:class:`UIObjectProxy <poco.proxy.UIObjectProxy>`>): iterable object of the given UI 
             proxies
            timeout (:obj:`float`): timeout in seconds, default is 120s

        Raises:
            PocoTargetTimeout: when not all of UI proxies appeared before timeout

def wait_for_all(self, objects, timeout=120):
        """
        Wait until all of given UI proxies show up before timeout.
        All UI proxies will be polled periodically. See option :py:class:`poll_interval <poco.pocofw.Poco>` in 
        ``Poco``'s initialization for more details.

        Args:
            objects (Iterable<:py:class:`UIObjectProxy <poco.proxy.UIObjectProxy>`>): iterable object of the given UI 
             proxies
            timeout (:obj:`float`): timeout in seconds, default is 120s

        Raises:
            PocoTargetTimeout: when not all of UI proxies appeared before timeout
        """

        start = time.time()
        while True:
            all_exist = True
            for obj in objects:
                if not obj.exists():
                    all_exist = False
                    break
            if all_exist:
                return
            if time.time() - start > timeout:
                raise PocoTargetTimeout('all to appear', objects)
            self.sleep_for_polling_interval()