Might be a small bug in moving the arm tutorial, how to correct such issues?

edit

I am using electric on Ubuntu 11.10

While going through the tutorial at : http://www.ros.org/wiki/pr2_controllers/Tutorials/Moving%20the%20arm%20through%20a%20Cartesian%20pose%20trajectory

I was unable to run it using the python client, But directly using the command line as explained worked nicely. I got

$python scripts/test_ik_trajectory_tutorial.py
Traceback (most recent call last):
  File "scripts/test_ik_trajectory_tutorial.py", line 69, in <module>
    success = call_execute_cartesian_ik_trajectory("/base_link", positions, orientations)
  File "scripts/test_ik_trajectory_tutorial.py", line 19, in call_execute_cartesian_ik_trajectory
    header = roslib.msg.Header()
AttributeError: 'module' object has no attribute 'msg'

This seemed like a straight forward issue and must be faced by other people as well, but I couldn't find the answer to exact error. Luckily when I googled with 'roslib.msg.Header()' and in google search page saw

#4784 (actionlib uses roslib.msg.Header instead of rospy.Header .............

I simply changed the

header = roslib.msg.Header()

to

header = rospy.Header();

and it worked!!!!

My question is : Is it specific to electric? Or only I am facing this? Or is it a valid bug? On my machine at /opt/ros/electric/ros/core/roslib/src/roslib/ there is no msg.py file but msgs.py and when I changed msg to msgs I got error on Header().

However if this is a valid bug (though small one then) how could it be corrected on the tutorial?