quickstart: module not found error: importlib_metadata

Hello, 
I am new to coding and data processing, so some help will be greatly appreciated. 
I installed the traffic library and got no error messages so far. Now I am trying to run the quickstart file, which was given here:  Getting started — traffic 2.8.0 documentation (traffic-viz.github.io)  to check if everything is working. 
But somehow I seem to be missing a module. I am getting this error code: ModuleNotFoundError: No module named "importlib_metadata"

Also: in my traffic - data - sample folder is no file or folder "belevingsvlucht". Shouldnt there be one?
How do I solve this error? I am a little lost
Many thanks!