This feels really hackish to me- what happens if there's another workflow method that has the highest possible priority? It also seems odd to have the core ```Workflow``` class define a workflow method, since (I think) those should only be defined by subclasses.

Maybe you could explicitly prepend the debug trace method in ```_all_wf_methods```? This way it can become a "private" method (e.g., ```_setup_debug_trace```) and you don't run into the issue of competing highest priorities.