code: def test_forward(self):
      losses = self.db_loss(self.preds, self.data_samples)
      assert "loss_prob" in losses
      assert "loss_thr" in losses
      assert "loss_db" in losses
  
file_path: mmocr/tests/test_models/test_textdet/test_module_losses/test_db_module_loss.py
imports: from unittest import TestCase
  import numpy
  import torch
  from mmengine.structures import InstanceData
  from mmocr.models.textdet.module_losses import DBModuleLoss
  from mmocr.structures import TextDetDataSample
label_desc: Use image node_id 5 for calling the TestDBModuleLoss obj's underlying member method code with example usage: obj.test_forward() without return types