code: def denoise_z15():
    
    hparams = xmoe2_dense_0()
    hparams.decoder_type = "denoising"
    hparams.noising_spec_train = {"type": "random_zipfian", "prob": 0.15}
    hparams.noising_use_eval_during_train = 0.25
    return hparams
docs: Replace tokens instead of masking.