code: def forward(self, x):
      msd_outs = self.msd(x)
      mpd_outs = self.mpd(x)
      mfd_outs = self.mfd(x)
      return msd_outs + mpd_outs + mfd_outs
  
imports: import logging
  import math
  from typing import Any, Dict, List, Optional
  import numpy
  import torch
  import torch.nn.functional
  from espnet2.gan_svs.visinger2.ddsp import remove_above_nyquist, scale_function, upsample
  from espnet2.gan_tts.hifigan import HiFiGANMultiPeriodDiscriminator, HiFiGANMultiScaleDiscriminator, HiFiGANMultiScaleMultiPeriodDiscriminator, HiFiGANPeriodDiscriminator, HiFiGANScaleDiscriminator
  from espnet2.gan_tts.hifigan.residual_block import ResidualBlock
label_desc: Use image node_id 2 for calling the VISinger2Discriminator obj's underlying member method code with example usage: obj.forward(x) and returns: unknown