Raspberry pi connecting to PX4 via mavlink (Dronekit-python)

I am tying to callback the mavlink common messages from pixhawk using raspberry pi 2 model B. I am using dronekit-python and a decorator to call the message
@vehicle.on_message(’ ')
def listener(self, name, message)
print message

But only some messages are working, eg. HEARTBEAT, GPS_RAW_INT, GLOBAL_POSITION_INT, etc
I am trying to callback the position from the fused accelerometer, and data from optical flow but the respective command are not working
Even HIGHRES_IMU is not functional.
Can anyone please give me a solution to this
Thanking you

Refer create_attribute_listener example available in Dronekit-python. use my_vehicle.py to set the mavlink parameter which you need, then callback it in another file. HIGHRES_IMU will get from RAW_IMU, SCALED_IMU etc in mavlink parameters.