def handle_pause_physics(self, req):
    'pause simulation, raise flag to prevent pybullet to execute self.pb.stepSimulation()'
    self.get_logger().info('pausing simulation')
    self.pause_simulation = False
    return []
pause simulation, raise flag to prevent pybullet to execute self.pb.stepSimulation()
def handle_pause_physics(self, req):
    
    self.get_logger().info('pausing simulation')
    self.pause_simulation = False
    return []