code: def test_from_str_wrong_input(self, string):
      self.assertRaises(
          ValueError, utils.string_to_loss_function, string
      )
  
imports: from unittest import mock
  from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  from tensorflow_privacy.privacy.privacy_tests import utils
label_desc: Use image node_id 2 for calling the LossFunctionFromStringTest obj's underlying member method code with example usage: obj.test_from_str_wrong_input(string) without return types