How to fix 'no module named actionlib_tutorials.msg error when going through the actionlib ros tutorials

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I'm going through the actionlib tutorials and I'm getting this error with the example python script:

Traceback (most recent call last): File "/home/leonard/catkin_ws/src/actionlib_tutorials/simple_action_servers/fibonacci_server.py", line 7, in <module> import actionlib_tutorials.msg ImportError: No module named actionlib_tutorials.msg This is very confusing because actionlib_tutorials does have an 'msg' file.

I am using ros melodic in singularity