code: def test_copy_loss_output_range_is_positive(self):
      for params, init_case in itertools.product(
          self.PARAMS, self.INIT_CASES
      ):
          loss = CopyGeneratorLoss(**init_case)
          dummy_in = self.dummy_inputs(params, init_case)
          res = loss(*dummy_in)
          self.assertTrue((res >= 0).all())
  
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 5 for calling the TestCopyGeneratorLoss obj's underlying member method code with example usage: obj.test_copy_loss_output_range_is_positive() without return types