code: def delLadder(name):
      
      ladders = getKnownLadders()
      try:
          ladder = ladders[name]
          os.remove(ladder.filename) # delete from disk
          del ladders[name] # deallocate object
          return ladder
      except KeyError:
          raise ValueError("given ladder name '%s' is not a known ladder definition"%(name))
docs: forget about a previously defined Ladder setting by deleting its disk file