code: def save(self, fname: str):
          
          obj = copy.deepcopy(self)
          obj.__del_frozen()
          with open(fname, 'w') as out:
              yaml.dump(obj, out, default_flow_style=False)
docs: Saves this Config (without the frozen state) to a file called fname.
  
          :param fname: Name of file to store this Config in.