Update test_lobster_tasks.py

Author: itsduowang

atomate/vasp/firetasks/tests/test_lobster_tasks.py

@@ -157,7 +157,7 @@ def test_mongodb_more_files(self):
         self.assertListEqual(load_dict["output"]["chargespilling"], [0.008, 0.008])
         db = self.get_task_database()
         gfs = gridfs.GridFS(db, "lobster_files")
-        results = gfs.find({}).count_documents()
+        results = gfs.count_documents({})
         self.assertEqual(results, 2)
         for fn in ["ICOHPLIST", "COOPCAR"]:
             oid = load_dict[fn.lower() + "_id"]