    def __init__(self, cfg, dataset, is_valid=False):
        """
        Args:
            cfg: config
            dataset: dataset name
            is_valid: whether to use train or valid dataset
        """
        super().__init__(cfg, dataset, is_valid)

        eval_index = random.randint(0, len(self.metadata) - 1)
        eval_utt_info = self.metadata[eval_index]
        eval_utt = "{}_{}".format(eval_utt_info["Dataset"], eval_utt_info["Uid"])
        self.eval_audio = np.load(self.utt2audio_path[eval_utt])
        if cfg.preprocess.use_mel:
            self.eval_mel = np.load(self.utt2mel_path[eval_utt])
        if cfg.preprocess.use_frame_pitch:
            self.eval_pitch = np.load(self.utt2frame_pitch_path[eval_utt])
Args:
cfg: config
dataset: dataset name
is_valid: whether to use train or valid dataset
models/vocoders/diffusion/diffusion_vocoder_dataset.py