code: def enable_tracing(self):
          
          hooktrace = self.hook._trace
  
          def before(hook_name, methods, kwargs):
              hooktrace.root.indent += 1
              hooktrace(hook_name, kwargs)
  
          def after(outcome, hook_name, methods, kwargs):
              if outcome.excinfo is None:
                  hooktrace("finish", hook_name, "-->", outcome.get_result())
              hooktrace.root.indent -= 1
  
          return self.add_hookcall_monitoring(before, after)
docs: enable tracing of hook calls and return an undo function.