diff --git a/airbyte-cdk/python/airbyte_cdk/sources/streams/checkpoint/checkpoint_reader.py b/airbyte-cdk/python/airbyte_cdk/sources/streams/checkpoint/checkpoint_reader.py
index 0c3e7426b5b7..1b6d63247206 100644
--- a/airbyte-cdk/python/airbyte_cdk/sources/streams/checkpoint/checkpoint_reader.py
+++ b/airbyte-cdk/python/airbyte_cdk/sources/streams/checkpoint/checkpoint_reader.py
@@ -95,7 +95,7 @@ def __init__(self, cursor: Cursor, stream_slices: Iterable[Optional[Mapping[str,
         self._read_state_from_cursor = read_state_from_cursor
         self._current_slice: Optional[StreamSlice] = None
         self._finished_sync = False
-        self._previous_state = None
+        self._previous_state: Optional[Mapping[str, Any]] = None
 
     def next(self) -> Optional[Mapping[str, Any]]:
         try: