class_docstr: One step decoder unit for hidden representation generation
  it can stack multiple vertical layers to increase the depth.
  
  Parameter
  ==========
  in_feats : int
      number if input features
  
  hid_feats : int
      number of feature before the linear output layer
  
  out_feats : int
      number of output features
  
  num_layers : int
      vertical depth of one step encoding unit
  
  net : torch.nn.Module
      message passing network for graph computation
class_docstr_tok: ["One","step","decoder","unit","for","hidden","representation","generation","it","can","stack","multiple","vertical","layers","to","increase","the","depth",".","Parameter","==========","in_feats",":","int","number","if","input","features","hid_feats",":","int","number","of","feature","before","the","linear","output","layer","out_feats",":","int","number","of","output","features","num_layers",":","int","vertical","depth","of","one","step","encoding","unit","net",":","torch.nn.Module","message","passing","network","for","graph","computation"]
code: def __init__(self, in_feats, hid_feats, out_feats, num_layers, net):
      super(StackedDecoder, self).__init__()
      self.in_feats = in_feats
      self.hid_feats = hid_feats
      self.out_feats = out_feats
      self.num_layers = num_layers
      self.net = net
      self.out_layer = nn.Linear(self.hid_feats, self.out_feats)
      self.layers = nn.ModuleList()
      if self.num_layers <= 0:
          raise DGLError("Layer Number must be greater than 0!")
      self.layers.append(
          GraphGRUCell(self.in_feats, self.hid_feats, net)
      )
      for _ in range(self.num_layers - 1):
          self.layers.append(
              GraphGRUCell(self.hid_feats, self.hid_feats, net)
          )
  
imports: import dgl
  import dgl.function
  import dgl.nn
  import numpy
  import scipy.sparse
  import torch
  import torch.nn
  from dgl.base import DGLError
  from dgl.nn.functional import edge_softmax
label_desc: Use image node_id 1 to create a new StackedDecoder object from inherited base classes: nn with example: obj = StackedDecoder(in_feats, hid_feats, out_feats, num_layers, net)