chore: fix closing of LMDB cursor in LmdbStore

sync_crawler/store/lmdb_store.py

@@ -3,6 +3,7 @@
 import pickle
 import uuid
 from collections.abc import Callable, Iterable
+from contextlib import closing
 from typing import override
 
 import lmdb
@@ -40,16 +41,19 @@ def put(self, news: Iterable[News]):
 
         with (
             self._env.begin(write=True) as txn,
-            txn.cursor() as cur,
+            closing(txn.cursor()) as cur,
         ):
             cur.putmulti(key_value_pairs)
 
     @override
     def pop(self, nums=1) -> Iterable[News]:
         values: Iterable[News] = []
 
-        with self._env.begin(write=True) as txn:
-            for key, value in itertools.islice(txn.cursor(), nums):
+        with (
+            self._env.begin(write=True) as txn,
+            closing(txn.cursor()) as cur,
+        ):
+            for key, value in itertools.islice(cur, nums):
                 values.append(pickle.loads(value))
                 txn.delete(key)