class_docstr: Derive a specific sub-class of a VAE for a CNN sentence model. 
class_docstr_tok: ["Derive","a","specific","sub-class","of","a","VAE","for","a","CNN","sentence","model","."]
code: def pz_params(self):
      return (
          self._pz_params[0],
          F.softplus(self._pz_params[1]) + Constants.eta,
      )
  
imports: import torch
  import torch.distributions
  import torch.nn
  import torch.nn.functional
  import torch.utils.data
  from numpy import sqrt
  from torchvision.utils import make_grid, save_image
  from datasets import CUBImageFt
  from utils import Constants, NN_lookup
  from vis import plot_embeddings, plot_kls_df
  from .vae import VAE
label_desc: Use image node_id 2 for calling the CUB_Image_ft obj's underlying member method code with example usage: obj.pz_params() and returns: self,  unknown