code: def output_state_dimension(self) -> int:
      return self.__output_state_dim
  
file_path: ptgnn/ptgnn/neuralmodels/gnn/messagepassing/mlpmessagepassing.py
imports: import torch
  from torch import nn
  from typing import Callable, Dict, List, Optional, Tuple, Union
  from ptgnn.neuralmodels.gnn.messagepassing.abstractmessagepassing import AbstractMessageAggregation, AbstractMessagePassingLayer
  from ptgnn.neuralmodels.mlp import MLP
label_desc: Use image node_id 4 for calling the MlpMessagePassingLayer obj's underlying member method code with example usage: obj.output_state_dimension() and returns: self