def METHOD_NAME(self, pre=False):
    goal = GraspGoal()
    goal.grasp = self.grasp
    goal.pre_grasp = pre
    client = SimpleActionClient('grasp', GraspAction)
    client.wait_for_server()
    client.send_goal(goal)
    client.wait_for_result(rospy.Duration.from_sec(20.0))
    if client.get_state() == GoalStatus.SUCCEEDED:
        rospy.loginfo("Success!")
    else:
        rospy.logerr("Fail!")