code: def process_message(self, msg):
      if msg["type"] == "sample":
          batch_shape = msg["fn"].batch_shape
          if (
              len(batch_shape) < -self.dim
              or batch_shape[self.dim] != self.size
          ):
              batch_shape = [1] * (-self.dim - len(batch_shape)) + list(
                  batch_shape
              )
              batch_shape[self.dim] = self.size
              msg["fn"] = msg["fn"].expand(torch.Size(batch_shape))
  
imports: import random
  import warnings
  import weakref
  from collections import OrderedDict
  import numpy
  import torch
  from pyro.distributions import validation_enabled
label_desc: Use image node_id 2 for calling the PlateMessenger obj's underlying member method code with example usage: obj.process_message(msg) without return types