code: def test_loss(self, mock_get_targets):
      imgs, data_samples, targets = self._get_drrg_inputs()
      mock_get_targets.return_value = targets
      losses = self.model(imgs, data_samples, mode="loss")
      self.assertIsInstance(losses, dict)
  
file_path: mmocr/tests/test_models/test_textdet/test_detectors/test_drrg.py
imports: import copy
  import unittest
  from os.path import dirname, exists, join
  from unittest import mock
  import numpy
  import torch
  from mmengine.config import Config, ConfigDict
  from mmengine.registry import init_default_scope
  from mmocr.registry import MODELS
  from mmocr.testing.data import create_dummy_textdet_inputs
label_desc: Use image node_id 4 for calling the TestDRRG obj's underlying member method code with example usage: obj.test_loss(mock_get_targets) without return types