diff --git a/src/questdb_connect/table_engine.py b/src/questdb_connect/table_engine.py
index 841ecd4..f777c6a 100644
--- a/src/questdb_connect/table_engine.py
+++ b/src/questdb_connect/table_engine.py
@@ -36,7 +36,7 @@ def __init__(
         ts_col_name: str,
         partition_by: PartitionBy = PartitionBy.DAY,
         is_wal: bool = True,
-        dedup_upsert_keys: typing.Tuple[str] = None,
+        dedup_upsert_keys: typing.Optional[typing.Tuple[str]] = None,
     ):
         sqlalchemy.sql.visitors.Traversible.__init__(self)
         self.name = table_name