code: def expected_shape(cls, params, init_case):
      return (
          params["tgt_max_len"] * params["batch_size"],
          init_case["output_size"] + params["n_extra_words"],
      )
  
imports: import unittest
  from onmt.modules.copy_generator import CopyGenerator, CopyGeneratorLoss
  import itertools
  from copy import deepcopy
  import torch
  from torch.nn.functional import softmax
  from onmt.tests.utils_for_tests import product_dict
label_desc: Use image node_id 2 for calling the TestCopyGenerator obj's underlying member method code with example usage: obj.expected_shape(cls, params, init_case) and returns: unknown,  unknown