Wait for an activity: block until target activity presents
        or time out.

        Android only.

         - _activity_ - target activity
         - _timeout_ - max wait time, in seconds
         - _interval_ - sleep interval between retries, in seconds

def wait_activity(self, activity, timeout, interval=1):
        """Wait for an activity: block until target activity presents
        or time out.

        Android only.

         - _activity_ - target activity
         - _timeout_ - max wait time, in seconds
         - _interval_ - sleep interval between retries, in seconds
        """

        if not activity.startswith('.'):
            activity = ".%s" % activity

        driver = self._current_application()
        if not driver.wait_activity(activity=activity, timeout=float(timeout), interval=float(interval)):
            raise TimeoutException(msg="Activity %s never presented, current activity: %s" % (activity, self.get_activity()))