Write this preset to disk in JSON notation.

            :param presets_path: the directory where the preset will be
                                 written.

def write(self, presets_path):
        """Write this preset to disk in JSON notation.

            :param presets_path: the directory where the preset will be
                                 written.
        """
        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)