The issue is https://github.com/RoelofWobben/banking_on_clojure/blob/master/src/practicalli/banking_on_clojure.clj#L6
Namespaces should use the
- (dash) in multi-part names within the source code, however, the corresponding file name should be an
_ underscore. This is due to a limitation of the Java virtual machine class loader and a small annoyance that we've all had to be come accustom too.
This namespace does not match the file name, so will not be found from the
:require directive in the backing-on-clojure namespace
I do get the impression from your posts across several slack channels that you are trying to learn a great many things at once. This often leads to getting easily tripped up on small issues like this. I had given you the answer to this issue 5 days ago. I appreciate it can be frustrating learning something new and would encourage you focus just a few aspect of Clojure at a time. Good luck.