NameError: global name 'ms' is not defined after running learning_tf start_demo.launch

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Hi. Running through the tf tutorials in sequence and currently at tfTutorialsWriting a tf listener (Python).

Run roslaunch learning_tf start_demo.launch and get following errors:

[ERROR] [WallTime: 1432379077.642128] bad callback: <function handle_turtle_pose at 0x7fd1eb45d6e0>
Traceback (most recent call last):
  File "/opt/ros/indigo/lib/python2.7/dist-packages/rospy/topics.py", line 709, in _invoke_callback
    cb(msg, cb_args)
  File "/home/andrew/catkin_ws/src/learning_tf/nodes/turtle_tf_broadcaster.py", line 12, in handle_turtle_pose
    tf.transformations.quaternion_from_euler(0, 0, ms.theta),
NameError: global name 'ms' is not defined

Can see the 2 turtles appearing in the window. Can move 1 turtle via arrow keys but 2nd turtle does not follow turtle 1

Note: have run apt-get update and lots of ROS packages updated.