code: def write(self, presets_path):
          
          if self.builtin:
              raise TypeError("Cannot write built-in preset")
  
          # Make dictionaries of PresetDefaults values
          odict = self.opts.dict()
          pdict = {self.name: {DESC: self.desc, NOTE: self.note, OPTS: odict}}
  
          if not os.path.exists(presets_path):
              os.makedirs(presets_path, mode=0o755)
  
          with open(os.path.join(presets_path, self.name), "w") as pfile:
              json.dump(pdict, pfile)
docs: Write this preset to disk in JSON notation.
  
              :param presets_path: the directory where the preset will be
                                   written.