code: def wait_activity(self, activity, timeout, interval=1):
          
  
          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()))
docs: 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