Custom ROS message with unit8[] in python!

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I have a PacketMsg.msg as follows in my package:

uint8[] buf

I would like to decode /topic with this sample python script;

import rospy
from ouster_ros.msg import PacketMsg

def cb(msg):
    rospy.loginfo('len_msg: {}, type_msg: {}'.format(len(msg.buf), type(msg.buf)))
    rospy.loginfo('msg: {}'.format(msg.buf)) 

def main():
    rospy.init_node("my_sub")
    rospy.Subscriber('/topic', PacketMsg,cb)
    rospy.spin()

if __name__ == "__main__":
    main()

This is the output printed in terminal:

[INFO] [1579270050.540915]: len_msg: 49, type_msg: <type 'str'>
[INFO] [1579270050.541343]: msg: ��H?�~�a�B��`����g=��?M��

whereas, $ rostopic echo /topic returns:

buf: [47, 185, 250, 245, 155, 0, 0, 0, 54, 238, 166, ....................... , 23, 154, 0, 0]

Does anybody know how to change such <type 'str'> to a list for further usages?

Cheers,