error: ‘__s_getMD5Sum’ is not a member of ‘boost::shared_ptr

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Hi ! I am trying to use message filters in ROS and here is my code.

message_filters::Subscriber<sensor_msgs::ImageConstPtr> image_sub(nh, "/camera/image", 1);
message_filters::Subscriber<sensor_msgs::LaserScan> laser_sub(nh, "/scan", 1);
TimeSynchronizer<sensor_msgs::ImageConstPtr, sensor_msgs::LaserScan> sync(image_sub, laser_sub, 10);
sync.registerCallback(boost::bind(&callback, _1, _2));

My call back function looks like this

void callback(const sensor_msgs::ImageConstPtr& img,const sensor_msgs::LaserScan& scan)

I am getting the follow error :

/opt/ros/noetic/include/ros/message_traits.h:120:28: error: ‘__s_getMD5Sum’ is not a member of ‘boost::shared_ptr<const sensor_msgs::Image_<std::allocator<void> > >’

120 | return M::__s_getMD5Sum().c_str();

What is the problem ? help would be VERY MUCH APPRECIATED! ty