code: def test_datastore_stats(self, dwc):
      cache_path = os.path.join(self.data_dir, md5_digest(self.studies))
  
      dwc.return_value.base_url = self.studies
      dwc.return_value.search_for_series = (
          lambda **kwargs: search_for_series(self.data_dir, **kwargs)
      )
      dwc.return_value.retrieve_series_metadata = (
          lambda *args, **kwargs: retrieve_series_metadata(
              self.data_dir, *args, **kwargs
          )
      )
      dwc.return_value.load_json_dataset = (
          lambda *args, **kwargs: retrieve_series(
              cache_path, *args, **kwargs
          )
      )
  
      response = self.client.get("/datastore/?output=stats")
      self.assertEqual(response.status_code, 200)
  
      res = response.json()
      total = res["total"]
      completed = res["completed"]
      label_tags = res["label_tags"]
      self.assertEqual(total, 8)
      self.assertEqual(completed, 3)
      self.assertEqual(label_tags["original"], 2)
      self.assertEqual(label_tags["final"], 1)
  
file_path: MONAILabel/tests/unit/endpoints/test_dicomwebcache.py
imports: import json
  import os
  import unittest
  from typing import Dict
  from unittest.mock import patch
  import pydicom
  from monailabel.datastore.dicom import DICOMWebDatastore
  from monailabel.utils.others.generic import md5_digest
  from .context import DICOMWebEndpointTestSuite
label_desc: Use image node_id 2 for calling the EndPointDICOMWebDatastore obj's underlying member method code with example usage: obj.test_datastore_stats(dwc) without return types