Submitting content that includes C++ classes

Hi, I apologise if this question has been answered before, but I could not find a conclusive answer. I’m working to submit a set of blueprints that use a couple of classes to provide custom nodes which simplify some mathematical calculations. Is this allowed or not?
The guidelines refer to code plugins, but I am not sure if including a few classes would qualify the submission as a plugin or not.

Thanks in advance!