code: def encode_to_prequant(self, x):
      h = self.encoder(x)
      h = self.quant_conv(h)
      return h
  
imports: from contextlib import contextmanager
  import pytorch_lightning
  import torch
  import torch.nn.functional
  from nemo.collections.multimodal.modules.stable_diffusion.diffusionmodules.model import Decoder, Encoder
  from nemo.collections.multimodal.modules.stable_diffusion.distributions.distributions import DiagonalGaussianDistribution
  from nemo.collections.multimodal.parts.stable_diffusion.utils import instantiate_from_config
label_desc: Use image node_id 6 for calling the VQModel obj's underlying member method code with example usage: obj.encode_to_prequant(x) and returns: h