docstr: Return the last layer of the lstm_hx as the output from a stack
  
  Refactored so that alternate structures have an easy way of getting the output
code: def output(self, stack):
      """
      Return the last layer of the lstm_hx as the output from a stack
  
      Refactored so that alternate structures have an easy way of getting the output
      """
      return stack.value.output
  
file_path: stanza/stanza/models/constituency/transformer_tree_stack.py
imports: from collections import namedtuple
  import torch
  import torch.nn
  from stanza.models.constituency.positional_encoding import SinusoidalEncoding
  from stanza.models.constituency.tree_stack import TreeStack
label_desc: Use image node_id 5 for calling the TransformerTreeStack obj's underlying member method code with example usage: obj.output(stack) and returns: stack