fix: do not update the result of locals() directly

Author: yoptar

ydb/topic.py

@@ -321,7 +321,7 @@ def reader(
         if not decoder_executor:
             decoder_executor = self._executor
 
-        args = locals()
+        args = locals().copy()
         del args["self"]
         self._check_closed()
 
@@ -342,7 +342,7 @@ def writer(
         encoders: Optional[Mapping[_ydb_topic_public_types.PublicCodec, Callable[[bytes], bytes]]] = None,
         encoder_executor: Optional[concurrent.futures.Executor] = None,  # default shared client executor pool
     ) -> TopicWriter:
-        args = locals()
+        args = locals().copy()
         del args["self"]
         self._check_closed()