Global name 'mu' is not defined


When I try the commands in bellow:
"Remember to have the launch file roslaunch kalman_filter launch_auxiliary_nodes.launch running in WebShell #1, and the launch file roslaunch kalman_filter kalman_filter.launch executing in WebShell #2. "

I received so many of the following error:

[ERROR] [1606131916.463110, 767.128000]: bad callback: <function odom_callback at 0x7ff3ac4bbb18>
Traceback (most recent call last):
File “/opt/ros/kinetic/lib/python2.7/dist-packages/rospy/”, line 750, in _invoke_callback
File “/home/user/catkin_ws/src/kalman_filters_files/kalman_filter/scripts/”, line 54, in odom_callback
NameError: global name ‘mu’ is not defined

Hello @cls,

You need to execute 1st:

roslaunch kalman_filter launch_auxiliary_nodes.launch

and 2nd:

roslaunch kalman_filter kalman_filter_demo.launch

Sorry for the confusion,