code: def __init__(self, hidden_size):
      super(LoopyBPUpdate, self).__init__()
      self.hidden_size = hidden_size
  
      self.W_h = nn.Linear(hidden_size, hidden_size, bias=False)
  
imports: import os
  import dgl
  import dgl.function
  import rdkit.Chem
  import torch
  import torch.nn
  from dgl import line_graph, mean_nodes
  from .nnutils import cuda
label_desc: Use image node_id 1 to create a new LoopyBPUpdate object from inherited base classes: nn with example: obj = LoopyBPUpdate(hidden_size)