docs: def run_dumper(self, dumper):
          """run dumber (once pr. engine)
  
          Args:
              dumper: dumper to run (function or method).
  
          The dumper takes the attributes experiments, farms, and barn as input.
          It does not return anything. But can, if the dumper designer feels in
          a bad and nasty mood, modify the input objects
          (for example experiments).
          """
  
          logging.debug("start dumper::")
          dumper(
              experiments=self.experiments,
              farms=self.farms,
              barn=self.barn,
              engine=self.current_engine,
          )
          logging.debug("::dumper ended")